Gearbox pre 99 post 99 any difference

[sim69bed]

Gearbox for my 1.4 T reg golf 5 speed has been fitted but now I have no reversing lights am told that it needs a different switch as gearbox fitted was a recon of pre 99 My old gear box does not look no different i'm i being blagged as i think it is an internal fault which is not making the switch

( long winded story on who fitted what when.gearbox supplied someone else fitted )

Please Help