Anyone looking for an original with matching numbers, etc would be disappointed. I do know folks that want to restore such a vehicle with original stuff. On the other hand, there are many (many many) folks who don't necessarily care about restoring to original condition, but instead want the body and frame to be in good shape (you said no rust on this one) and running good. That replacement engine with lower miles and fuel injection sounds good. The auto tranny might be a bit of a tougher sell. I have auto and love it. But I don't rock crawl or do mudding in my Jeep. Mine is a daily driver in Houston traffic and sees some camping and deer hunting trips for its offroad use.
Fully restored and fixed up nice (new paint, frame cleaned/painted, etc)
CJ7's are selling for $17K - $40K on Hemmings, some higher with LS motor swaps. But Hemmings is usually a bit high. A few examples of comparable CJs:
84 CJ7 with fuel injection for $29,900
86 CJ7 inline 6 and manual for $16,900
Other comparable listings from eBay:
84 CJ7 Laredo inline 5 and manual with lift, winch, 35" tires for $12,500
77 CJ7 with V8, auto, lift, 35" tires, winch, full cage, lockers for $10K
For the one you've described and pictured, and without knowing stuff about the axles, gearing, what the wiring looks like, the interior condition, looks like regular bumpers, no lift, stock wheels, not knowing what might be hiding behind those rear corner guards, condition of gauges, etc, as a buyer I would be targeting the $10K - $12K range after a satisfactory test drive.
Just for reference, mine is an 84
CJ7. I have a fuel injected V8 and auto trans. With other upgrades (lift, tires/wheels, cage, bumpers, axles, winch, lights, audio, etc) as part of my build, I'd need $45K to let mine go ($50K with the matching trailer). Mine started out as an inline 6 with manual and some gauges not working, hard top and doors, along with 2-piece axles in the rear
Dana 20 and 3.54 gearing. It did have new paint, a lift, 35" tires and custom wheels and the winch already on it (quite similar to the eBay listing I referenced above). I paid $12,500 plus shipping to get it off Craigslist.