I'd stick with the 37mm stats - the 3pdr has only 2/3rds the muzzle velocity than the 45mm gun on the T-26, which is as good as (close enough) in real world and game stats to the 2pdr. The 2pdr was supposedly streets ahead of the earlier British ATGs so I'd try to keep it as "the best" - but then , it's fantasy so who am I to talk
Might want to reduce the AP range though if the HE was bad - don't suppose you've any good source on it's effectiveness in the HE role? The original naval version was ok, but is it a lack of good ammo, a doctrine thing (tanks shoot tanks! Infantry is left to artillery!) or did they knacker the HE aspect to get better anti-armour?