Puch made 10-speed bikes for Sears in the 60s and early 70s. I don't think that these were ever labeled as Free Spirits, but were Ted Williams brand (what the heck did he know about bikes, anyway?). The top of the heap were made with 3-main-tube 531 construction, and spec'ed with parts as needed to fit whatever price-point that Sears was aiming for (read that...low end parts were the norm for these bikes).

This is your bike, right? Nicco thinks that it is 531 (ignore the smish-smoosh of parts on this; it has been seriously retrofitted.) The following was posted as a way to tell from the head badge if you have a Puch:

"...Look at the headbadge. If it is a diamond shape with rounded corners and the Sears logo is in a circle, it is either made by Puch, President (Germany), or a Derby(Poland). The country of manufacture is usually in VERY small letters on the headbadge..."

Nicco's headbadge is gone, and I can't see yours from the picture that you posted...and I sucked that quote right off of the webz, so I can't speak to the veracity of it. Gives you some smoking gun kinda evidence if it is supported by your headbadge, though.