I'd not think to start making any
assumptions about what one or another local or regional crime lab might, or might not, do (or be able to do) with any specific firearm used in an incident in a potential criminal case.
Nor would I care to start
assuming what some paid expert might want to do in the way of examination of a firearm in some civil case (where the gun may still be in evidence and subject to examination). Private 'expert' examination? A representative from a gun company asked to examine it?
I'd also not dismiss out of hand the possibility that some experienced LE agency firearms armorer might be asked to examine a firearm involved in a criminal case. Not uncommon for a cop - (who is an experienced firearms instructor and/or factory trained armorer, or maybe even one who is also a gunsmith) - to become accepted as an expert witness in one or another court, and perhaps be asked to lend his/her experience and qualified expertise to examining a firearm.
Hey, I've heard an occasional gun company armorer instructor (meaning in more than one armorer class) caution armorers about making unauthorized modifications in a firearm which might, for whatever legal reason, later be examined by someone from the company.
We were warned that unauthorized (other than taught, etc) modifications, which changed the gun to a condition other than as originally manufactured & assembled, would probably be identified as such by a factory representative (for example, if called to examine the gun under subpoena, etc). How that might be accepted by some juror, in either a criminal or civil case, might be a headache some folks would wish to avoid. Might be a costly issue to overcome, too, when it comes to billable hours and legal fees (other experts, etc).
Now, I thought the article by Marty Hayes seemed pretty reasonable and objective.
His background and experience would seem to make his observations, opinions and thoughts of some interest, at least to me.
Meet the Firearms Academy Staff