1918/7-S Standing Liberty Quarter?

I just checked the date area of your coin at 1000% zoom level and compared it to the photo in

"Bill Fivaz's Counterfeit Detection Guide (pocket edition 2001)"

and it does not match the diagnostics and photo of a genuine 1918/7-S overdate variety.

Diagnostic #2 states "the 7 has a site curve to it, and fills the right side of the upper and lower loops of the 8."

While your coin look like it may be a 7 in the upper loop, the bottom loop shows no sign of the 7 inside it.

I also checked diagnostic #3 that shows a small (raised) die chip which shows up on most genuine overdates to help confirm the overdate, and while most, but not all genuine overdates have this die chip, it would have helped had your coin had this chip.

I'll let other's chime in for their opinions.

still a nice looking coin

The mintmark appears to be in the wrong spot as well. On your coin the mintmark looks too far from the star for the 1918/7 die.

It looks like they made many attempts to sell it starting at $399.00 or so. Somebody finally bought it.