[RSwank]

I am not aware of any such database. I have been able to make "possible" identification of planes based on gun serial numbers in certain special situations. If the plane is still fairly new it may have many of the original guns as installed in the factory. If you look at losses of planes whose serial numbers are close together (i.e. planes built at the same time in the same factory) you often see that the gun serial numbers are from the same manufacturer and they are all "close" together. The assumption is that the gun manufacturer(s) sent completed guns in large batches with serial numbers sequential (or very close together) and they ended up at the same plane factory. Thus planes being built at the same time at that factory would end up with gun serial numbers "close" together.
Sometimes there may have been a couple gun batches from different manufacturers, so you may, for example, see several High Standard guns whose serial numbers are close and then another group from Frigidaire.

Now the longer a plane flew in combat it becomes more and more likely that the "original" guns were changed out and then this method fails. This same type of argument can apply to the engine serial numbers (if a plane still has its original engines).