An older Smith with a rack full of go-gauges and a few dummy rounds can often quickly identify a chambering without charging a penny. A chamber cast offers more information, but there really aren’t so many options. As was recommended at the beginning of the thread - “if a .30-06 case chambers, you know it isn’t an 8 Mauser.” - if a 30-06 go gauge closes, an 8 Mauser it ain’t. If a a 30-06 bullet falls free in the muzzle, it ain’t a 30-06. If it has a belt step and a magnum bolt face, it ain’t an 8-06. Very, very quick determinations like that can be made with only a rough caliper measurements, a couple dummy rounds for bore checking, and either some empty cases or go gauges.
Lazy? Eh. Considerate? Damned straight. Any time I’ve done a chamber casting, I typically hold a rifle a few days and get my poop in a group, and I charge my labor time plus consumables + 10% over cost. When I was working under Van and had hundreds of gauges and dummies at hand, the 20min conversation with the customer plunking and measuring, then handing back an identified rifle - for free - almost always yielded return customership and word of mouth referrals - and of course, no entry in the log book. Equally, most often when a simple go-gauge and bullet/bore check didn’t yield a definitive answer, it meant a lot more time of research once the casting was done to figure out WTH I was holding.
Alas, that was 20+ years ago and I don’t have that catalog of gauges at hand any longer, scattered to the wind years after I left Van and he finally passed - with me too broke to buy out his entire inventory. In more recent years, I was stuck casting a lot more often than I’d have liked. But cerrosafe is universal and cheap, compared to dozens of go-gauges.