Should My Transom Have an Arc

[tartuffe]

I am rebuilding my transom on my 81 V20 center console. The existing rotted transom was in 3 pieces cut at an angle and it looks like this was done in order to bow the transom out about 3" from straight.

Was the transom originally flat or 3" of bow? My guess is that it was flat and 31 years of motor pressure bowed it out and at some point a patch job was done.

Any insight is appreciated