Are all WA inner barrels the same..?

[Wai Hoong Chan]

Im thinking about getting a longer inner barrel for my WA Para Ordinance.

 

http://www.x-fire.org/01/e.h.main.html

 

I just wanted to know if their barrel design is uniform throughout their range of colt pistols?

 

 

I also would like to know the length of a standard length Para barrel please.

 

Cheers