AN/PEQ-15 question

Howdy folks, apologies if this has been asked before but I was not able to find a similar question posted.

I swear I have heard a few people mention that older DOM PEQ’s can be more desirable (contingent on condition obviously), but I have been unable to source why that is. Was there a change in the manufacture/quality after a certain date? Or perhaps just less stories of malfunctions and failures reported form earlier models?

Any insight would be greatly appreciated, or even any links to good information about the details or history of the AN/PEQ-15 would be awesome. As I enjoy spending my free time trying to learn about shit like this rather than being productive in real life LOL

Thanks in advance!