My understanding is that the 1171/633 began being produced around '70/'71, and if I'm not mistaken a 29.xxx.xxx SN would likely be from around mid-'70 from other examples I've seen...
@gemini4 had a pretty nice table from a while back in the thread below. It also indicates that the 1171/633 began somewhere around 1970, but notes that it should be viewed with some elasticity. Perhaps someone has narrowed these dates down since then.
https://omegaforums.net/threads/bracelet-question-1171-1171-1-1171-633.39833/Click to expand...