37R's, are as have been described above, are solid rib models. they either would have been shipped with a brass bead (as my 1949 has) or the RayBar sights, that came on the scene in the late 50's/early 60's.
special order, or "Deluxe" models could have been shipped with other sight bead options.
the ribs are "soft soldered" to the barrels, as such, they cannot be hot blued or the rib will come off. If a person buys one and wants it restored, the barrel has to be old fashioned rust blued by someone who understands what they are doing so as to not ruin the gun.
Full choke guns surface the most, then Mod chokes.
The 2 Holy Grail guns for the average person to find would be either a 20 or a 16 ga, in Imp Cyl, followed by a 12ga from prior to 1954/55 (when the stock designed changed, I would have to consult my book, I don't remember which year exactly).
Equally as nice and desirable, would be the "Standard Grade Deluxe" models that started to be produced in the mid 50's. They shared the hand checkered buttstock of the earlier years with a finger grooved beaver tail forend. I have a 1957 field barrel gun in the Std Deluxe configuration.
Of course Ithaca put out higher grades, but they are fewer and further between and tend to command much higher prices.
Additionally, solid rib guns that have had poly-chokes put on them surface. They don't bring as good a price as an unmolested version.
My 1949 is in better than 90% condition. It has the added benefit that during the time when Ithaca was in King Ferry NY (and maybe even still in Ithaca NY) the company would make barrels on the old barrel thread pattern to be fitted to the old guns.
I have a barrel made during the 1970's, with Vent Rib and choke tubes, fitted to my 1949 receiver.
It is of course a 16ga, which is what I focus on.
I found a 1961 date of manufacture solid rib 16ga gun for my neighbor in a local gunshop. It is a 16ga with a Mod choked barrel. It is pretty cool. It is the Deluxe Std grade, but by 1961, Ithaca had quit using the stock patterns from the early 50's and were simply hand checkering the stocks that came on the standard grade guns.
The finger gripped beaver tail forend was still in use. These pictures show what a Deluxe Standard Grade will look like.
I am restoring this gun to factory new specs. It had some rust pits on the barrel that I had welded up by a shop that has a lazer. The lazer will not heat up, nor deform the thin walls of a shotgun barrel.
The pictures after the one showing the barrel pits are of the 1949 16ga. It has the 26" VR barrel on it at the time of the pictures.