My guess is 60's just due to windshield but not sure.
That certainly looks like a '69 -'71. It's a great looking boat. Looking down the side to the stern i see the Formula logo is a stylized script. The logo changed to a block format in the 70's. Another tell would be the instrument cluster. While it may have been deleted when is was worked on, the basic gauges would be incorporated within a single metal panel housed on the helm. You can check photos in my album of a 69 233 I almost bought. (no paper work) and check Formula's site. Here is a link to a page that they have posted with brochures dating back to 1971. https://www.formulaboats.com/brochures/vintage-formula-brochures/. These are actually located under the Owner Resources then Brochures. I have seen many boats this age that are missing HINs due careless work when repairing or refinishing. The serial number plate for this year boat was located on the cockpit side of the ring deck above the engine cover. An example of an serial number plate of this vintage is in my album.