Thanks for the hint Woodman. No markings on my follower.
My 3-set Forster gauges came in the mail today from Fulton - I figured it was a good investment as I'll likely rebarrel some lonely neglected sporter at some point.
Well - the jury is in. I took the ejector off my bolt, slipped in the go gauge and wouldn't ya know, bolt only goes halfway down. My chamber's shouldn't isn't THAT rough! The little bit of friction I was noticing on a "good" case was just the chamber pushing the shoulder back a few thousandths, or the base of the case grinding on the bolt face.
A bit frustrating, but I am kind of excited to rent a pull-through finish reamer and complete my first chamber! I checked all my other '03s while I was at it, and they all close on the go, and fall 1/2-1/3 short of closing on the no-go.
UPDATE: I was looking at https://www.reamerrentals.com - they rent a pull through reamer. From what I've seen, as long as I don't require an interchangeable pilot the pull through would be the easiest to maintain uniform pressure, as opposed to using a t-handle and rod. So, I slugged the bore to make sure - I got exactly 0.308 on the grooves, and what I think was 0.300 on the lands (a bit hard to measure from the slug with a 5 groove barrel). I know of 4drentals.com as well, but their descriptions don't say whether they include the handle or not. I'm not sold on finish reaming it - since it does close on a case most of the time. I may try polishing it as suggested first. Then again, the bolt is nowhere near closed on the go gauge, so maybe those SA replacement barrels were short chambered, and whoever put the barrel on never finish reamed it at all.