Anybody know how to date code a 60's Good Year tire?

[dannystarr]

I want to see if my spare is original to my car. Or at least DATED to my car. The code on the tire reads TY0549C  I read online that the "T" is '68 and the "Y" is May. Is that correct, and if so... what are the other numbers and letters? BTW I think I read that info on Team Chevelle... Danny

[1968RSZ28]

http://www.camaros.org/forum/index.php?topic=12259.0

Paul