Is it possible to add the craftsmanship bonuses/penalties to archeotech or do they always use the same stat block by the rules?

Generally all Archeotech is going to be of the best quality to begin with since that is the only thing that is going to survive for the tens of thousands of years the item in question has been around.

You could certainly add in Craftsmanship modifiers if you think it will add something, but I would tend to keep it simple.

Rules as written Craftsmanship applies to Archeotech like any other component.

If its in spectacular shape, make it BEST. If its beaten up and hurt, make it POOR. Up to you.

One can easily see how an archeotech laspistol, passed down through generations and lovingly maintained by expert craftsmen might be normal quality. Its been well maintained but thousands of years of use are still going to tell. Contrast with an ancient stasis vault, raided by a rogue trader who finds an archeotech laspistol in the SAME state is was in when the stasis field was active. This might be best quality. Contrast with an archeotech laspistol found in a sealed steel casket at the bottom of a hive sump. Its been well protected by the casket but **** and other stuff has soaked in a little. Once cleaned up it might be por quality.