G&G MP5 Recommend A Gearbox

[droog67]

This will seem a really simple question to most of you, but, as i don't know, so i'm going to have to ask.
I've a G&G MP5A4 in parts as a build project. Virtually everything except a Mecha-Box (gearbox), would any Version 2 Box fit ??
I've had AEGs off and on for years, but never had an MP5 apart.
I have the motor with it, with the correct length spline/gear-spur.
I'm a little cautious of buying a second-hand one, as i know new G&P mech-boxes are available for as little as £75.00
Thank-you for any help.