It's most likely the newest generation because the demand for firearms is so high that I highly doubt this is old stock. But as others have said there's only one way to know for sure and that's to contact buds customer service at 859-368-0371 Monday thru Friday 9am to 9pm. Sorry couldn't give a definite answer but hope this helps some.

You could also just go with a P365X. These were released in 2021 and have the full size grip of the "XL" and the shorter Barrel/Slide of the standard P365. It holds +2 in a flush fit mag over the standard version, plus it comes optics ready, if that's something your into.
Several in stock here
budsgunshop.com/search.php/type/Handguns/other/in_stock/q/P365X/sort/relevance />

Jason, you will need Buds Customer Service to confirm the Generation with their Inventory Dept. at 859-368-0371, 9am-9pm eastern Mon-Fri Or use the Blue Chat now button at the bottom right corner 9am to 9pm Mon - Sat and closed Sunday

I recommend contacting customer Service: 1-859-368-0371 9am-9pm EST Mon-Fri. Or use the blue "Chat Now" button at the bottom right corner 9am to 9pm Mon - Sat and 9am to 7pm Sunday. I hope this helps!

It is likely the newest gen, but sig doesn't make any identifiers specific to generation, they also don't label them "Gen1/2/3" etc.
The only way you could know for sure is to contact buds customer support and get a serial number, then run that by sig.
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Call buds during buissnes hours at 859-368-0371, 9am-9pm eastern Mon-Fri
Or use the Blue Chat now button at the bottom right corner 9am to 9pm Mon - Sat and closed Sunday ---------
Sig customer service
CUSTOMER SERVICE
603-610-3000 OPTION 1
8:30am – 5:00pm EST.