Parker was developed as a tougher coating to replace bluing. As I have read it's thicker more granular in nature. Why sometimes a parker finish can be kind of course looking. While better than unfinished steel, it still requires oil to help keep the moisture out. Think of it as a sponge with holes in it, to hold the gun oil next to the frame. It is of course not perfect, and will show wear. But then, wear shows that you actually shoot the thing. I'd not worry about the finish as long as it's mostly intact.
I have a Springer Ultra Compact on order in Stainless. I'm hoping that my bigger oopsies I can buff out at home. Clean, oil and use. My local shop had a Rock Island 3.5" comapct last month. I passed it by, due to, it had a rougher parker finish than I like, would have ended up sending for black nickle, and the biggest, the sites were military and would have required me to have Novak sites cut into the slide. Those two would have put me past what I have on order with the Loaded Springer.
As for the full length guide rod. There are lots of people against here on this board. The sales pitch for, I've seen.. by controling the spring by a rod internal (closer fit to the ID of the spring) is more consistant than controling it by the OD of the spring, more room in the frame, thus allowing the spring to bend more..... Frankly, it makes sense that the action of the spring would be more consistant with a FLGR. Enough that we'd notice? Maybe not. Certainly can't hurt. I think I've seen more complaints that a FLGR requires a tool or more time to strip. UMMMM OK.. I'm pretty sure 99.99% of us, strip and clean our 45s at home on a bench full of tools and cleaning parts anyway.
5-6 lbs trigger. Sounds about right.. now is it a smooth non creepy 5 lbs? That's what you want fixed.. Make sure there is no creep or drag in the trigger action. much lighter pull than that in a everyday gun might lead to trouble. If it's your dedicated competition gun, sure go lighter.. once you have a 2nd, 3rd, 4th normal home defense gun available.