67/68 had the timing mark roughly in line with the keyway. I think it's actually about one or two degrees counter clock wise from in line with the keyway.
The 69 up balancer has the mark moved around 10 degrees counter clockwise from the keyway. Or about 8 degrees from the earlier mark.
All that was on there origonally should be a cut line for TDC, no stamped letters.
Don't know about the timing cover.
Check my web page for First Gen Camaro suspension info:
David's Motorsports page
First Gen Suspension Page
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Chev 350
Can Am Vintage Racer