Chalam,
I don't think the true shape of the cross matters that much either.
Besides Barnabas there is even graffiti found dates to the second century that shows a cross too.
My issue with the WT making the shpe of the cross and issue ( they did it, no one else did) is that, while they are right to say that ANY image shoudl not be worshipped they seem to forget that Paul BOASTED about the Cross and Jesus dying on it, it is NOT a bad symbol but a symbol of love and hope or at least Paul saw it that way.