[mrerick]

Here's my relatively inexperienced take on this:

A collectible Luger is one that is as close as possible to the original factory state. It is valued for both it's mechanical and appearance aspects being exactly what the factory made.

Starting from original factory state, it's condition (and value) descends. It's valuation is based upon demand, rarity and honest condition.

Some things remove a Luger from being considered collectible. On a more common Luger, a mismatched part (ranging from things where the numbers are quite hidden, through entire sub-assemblies) can do this. Finish wear expressed as an original finish percentage below 85% or so... Pitting and other exterior damage... On most Lugers, refinishing - especially incorrectly... (note that Swiss Lugers were typically refinished during arsenal reworking and this generally doesn't make them non-collectible); Import marking - although this is changing for more rare or unusual original Lugers that have subtle markings...

Non authentic markings or attempts to "boost" a Luger generally eliminate it from collector interest.

Matching magazines, being unusual, increase the value of a collectible Luger.

Everything else that functions properly would be valued as a shooter. Things that don't shoot properly would be parts...