I don't own a Inland 'Late Enough' to have a hand stamped 1.
There are collectors out there that have or are trying to acquire a carbine from every Prime maker's assigned serial number blocks, not just one from each maker.
Some even digging further yet looking for the rare spring tubes, line-outs, sub contractor supplied receivers, transitionals, duplicate and over run serial numbers.... etc.
What makes Hand stamps interesting to me is they're late production carbines mostly found with the latest upgraded/improved parts.
Makes me think, that with these Carbines having the most improved/advanced parts at the time, that they'd give one the best overall performance.
Upgraded parts, mean't they worked better. Be it better timing and ejection from the Op slides and Bolts...... to mag catches with support arms to support the weight of 30 rd mags.
Rears sights now adjustable for windage .... better elevation. Barrel bands with better lock down, and stocks-hand guards bulked up to limit cracking.
These just to name a few of the late improvements associated with hand stamps.
Some have also said with being later in production, there may be a better chance of owning a carbine that has been shot/used less..... I do think those who have said that were referring to the M1hand stamp...........
Last note: Being later production, if needed a replacement part should be easier and cheaper to pick up than say...... Replacing a Flat Bolt for a S'G'.
Just Some Thoughts,
Charlie-Painter777