Are you asking if, when pistols are used in melee using the Yaktribe Community Edition, they have the strength of the pistol rather than the strength of the user?
"a sword, knife, pistol etc. Resolve the hit using the Strength of the weapon as indicated in the Armoury section." - Necromunda 2003.
Yes, melee hits with a pistol use the strength of the pistol rather than the user, hits with a chainsword use the strength of the chainsword rather than the user, etc. When using two weapons, the hits are divided evenly between the two weapons - in your example, half the hits would be with a bolt pistol (S4) and half with a knife (user's S).