that's not a Space Compax bracelet. The original is a Gay Freres product with UM endpieces. I can't identify the manufacturer on this one (triangle HC) and the endpieces are blank, so it's merely a 20mm UG bracelet. If the dating works the same way it does on the Zenith lobster bracelets, it is from late1974, which post-dates the Space-Compax.
Here's the proper goods
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