bryan - the Screw-grip boxlock came in, I believe, ten levels of original quality grade. These are not the same as the W&S Series guns, far as I know. They all left the factory as very servicable guns. Current condition level will be far more important than original quality level , in this case.

The Brand Value of Scott is BV3. The description of the action as devoid of engraving places this gun at the bottom end of boxlock quality. Note that it is very rare for the extent and quality of engraving coverage and quality of the wood not to go hand-in-hand with the actioning and barrel quality. Lets say it is an OQ7.5 - OQ7 is expected to have border engraving and OQ8 is a plain BLNE. The current condition level, considering there is no case color, can't be higher than CC4 (heavy use but no abuse). If you suspect it will need some repairs soon, then you will need to reduce the CC a notch or two.

BV3-OQ7-CC4 = $1233 and BV3-OQ8-CC4 = $771. Asking price seems about right if we have gotten OQ and CC near correct. If it is a BV3-OQ7.5-CC5 (minor repairs needed or restoration accomplished) = $750.

The fact of 2 1/2" or 2 3/4" chamber is a very low priority question as you will need to shoot low pressure loads no matter the chamber length. Let me say that again - in no way does the presence of 2 3/4" chambers, neither factory nor reamed, make this gun suitable for typical American factory (SAAMI standard) loads. It will require CIP standard loads, factory loads of known low pressure, or handloads to known low pressure formulae (which may very well be assembled in 2 3/4" cases - you must use low pressure loads, though). Also, you will likely find the gun more enjoyable with shot loads in the 7/8 oz range and held to 1100 fps, especially if you will shoot clay target volumes of shells. Low recoil is kind to you and the wood. Low pressure is kind to the action metal.

This sounds like a candidate for an economical entre into SXS shooting - IF, BIG IF, the gun is truly sound and you are willing to feed it the required diet. pictures would be very helpful.