I agree that an Allen head would suck for the reasons listed. I've stripped out plenty of Phillips head screws. That's why I suggested a Torx head in the email.
I bought some wood screws yesterday for $3.99 that were Torx head. I was tired of stripping out the phillips head screws. They thoughtfully included a Torx bit in the package. I don't envision needing to constantly change or adjust the sight once zeroed and secured, so not carrying a Torx bit in my pocket shouldn't cause a problem.
The white screw, to my mind, makes it look cheap. Like you ran out of the correct screw, so used this one instead to get the sight out the door.
Why not put a black finish on a stainless screw?
Regardless, I would buy this sight as is.
I can comment regarding machine screw drive recesses and available finishes for stainless steel fasteners.
On the drive recesses: With flat head screws, recesses with vertical drive recess features (hex-socket head or "Allen", six-lobe or "Torx") are at a distinct disadvantage because the minimum required depth of these recesses limits the size. One must use a small size recess since going larger will weaken the fastener at the head/shank junction, or limit the depth of the recess. The obvious advantages of these types of recesses is the lack of need for an axial force to minimize the chances of "cam-out". The small recess size, however, greatly increases the risk of stripping the recess. Take a look at various flat head screws with the above mentioned recesses and you can see that the size of the recess is disproportionally smaller than the shank size.
There are exceptions to this limitation that have been successfully used in various construction type fasteners. I commonly use a flat head drill screw for wood fastening that has an excellent six-lobe recess for this application. The screws are made of a hardened steel alloy and they are used in wood which has much less tortional force requirements for seating than in metal.
Enter the Phillips-type recess. The angular shape of the Phillips recess lends itself to the tapered shape of the flat head. The outside edges of the Phillips driver has a much better mechanical advantage than the outside edges of the recesses mentioned above. Physically, it is a better match. The downside to this is the tendency for a "cam-out" action that will quickly (and very effectively) destroy the recess. This is especially true with metal fasteners used to assemble metal parts.
Phillips-type recesses can be very effectively used if three very important rules are followed:
1)
Match the driver to the recess. If a particular screw has a Phillips #1 recess, use ONLY a #1 Phillips driver. And this driver MUST be in good condition. Generally, if the driver is damaged such that it does not make a clean, full depth contact with the screw recess, it has been abused in the past, or is worn out, and should be discarded. Properly used Philips screwdrivers will last many, many years before needing to be replaced, but they must be replaced if worn or damaged.
2)
Apply sufficient AXIAL force when tightening or loosening Phillips-type screws. Axial force is applying force along the axis of the fastener. My rule of thumb is to push with more force than I use in turning the driver. Preventing cam-out is key here and applying significant axial force (along with rule #1 above) will minimize the tendency to have this happen. Pushing strongly on the fastener is conducive to relieving forces that can prevent easily loosening and can aid in tightening.
3)
Driver/fastener alignment. It is also imperative (as are rules #1 & #2 above) to have the shank of the driver be coaxial (in alignment) with the shank of the fastener. The better the alignment, the more effective rule #2 is.
So, matched Phillips driver to fastener recess, strong axial force, proper coaxial alignment.
If you are still awake, there are finishes that can be applied to stainless steel screws to make them black in color. They add cost and complexity to the fasteners in question and care must be taken to be sure of proper thread fit once they are colored. One is black nickel plating, the other is black nitride with a trade name of DuraBlack. I don't know enough about these methods to comment on them, but they are available. To me, it wouldn't be worth the hassle since when I am aligning the sights, I couldn't see the screw anyway.
Gun bluing using standard carbon steel screws is another way. These may be available commercially but since the screw in question is a custom length, this would have to be dealt with as a custom defined fastener.
Just my $0.02.
Dan