[Travistee]

I've read here about some of the newer serial number guns having improvements over the older ones.

How can I tell if I have a newer or older one?

Mine starts with H3xxx

 

[Flyer]

Sounds like you've got one of the very latest ones!
An H3# is as high as you can expect to get right now... H4# should be coming along fast, though, at this rate!
Flyer

 

[Jbarn]

Mine is 01579, what's that mean? Have'nt noticed anything really needing improvement.

 

[Flyer]

Jbarn,
Nope, if it's working well, nothing to worry about! Most of the "Upgrades" were actually small changes in parts to correct specific problems... if yours doesn't have any problems, there's nothing to correct!
Flyer