It may or may not be a Ram Air III car and the PHS documents will be the way to confirm this.
Seeing the original engine is not with the car, the block number really does not matter. The '69 engines were stamped with the last 9 digits of the cars vin -so it can't be replaced. Block code was "WS". Again, not really something you need to pay top dollar for just to say you have the "WS" code block that is not Vin stamped. The next thing is that you would have to also match your date codes cast into all parts to match the build date of your car. So this would present a tough search and top dollars paid out -if you could find it all.
The correct head casting number for a manual trans RAIII is "48".
To put a price on any car is tough whether "as is" or "finished." Its been said many times, "Its only worth what someone will pay for it." As is, the car sounds rough and will need extensive sheet metal work (will all the lower areas rotted out, how is the frame?). Vinyl roof -most likely you will find rot along the lower vinyl around the rear window glass. Lower front windshield channel is another sore spot. It'll need a replacement engine. No doubt you will need to rebuild the front suspension, rear suspension, brake system, and whatever interior items it needs. This car sounds like it is in need of a complete frame-off, or close to it.
Personally, I see a big project with a big investment. Is it worth it? IF it turns out to be an original RAIII car, the value will not increase much as the engine is the value in that car. So your next option is to rebuild/restore the car to a stock configuration OR do a "resto-mod" which allows you to put your influence on the car -basically restoring the outer body and putting your spin on the drivetrain, interior, wheels/tires, etc..
The more work you can do, the more you save. If you have to farm out all your work, then your investment will go way up. If you do have someone do most of the work, then in my opinion, you will find you have more into it than what you can sell it for -IF you plan on selling it. When you begin to weigh the amount of work and costs to restore/rebuild your project, you may find that it was more cost effective to purchase outright a turn-key car that you can enjoy "now" and not years from now. But, if you are like many of us, it is the joy and satisfaction of working on and rebuilding your own ride even if it costs a boat load of cash and takes many years to complete. It's about accomplishment and the ownership of that accomplishment that really makes you feel proud of your car, however perfect or imperfect it turns out.
That said, I would not get too pumped thinking it is a cash cow because it may have been a RAIII car. The engine, the most vital part, is gone. To reproduce it will never get back the original engine and will never command a selling price an original numbers matching car would. The costs to attempt to gather all the matching/date coded parts would be hard to assemble and expensive. You would be better to invest wiser in a different approach on your engine of choice. With all that it needs in its rebuilding, there is a better than probable chance that you will be upside down on the car and selling it may see a loss to you. If you build it to keep and "will yourself to be buried in it", then what monies or time you put into it don't really matter.
This is not discouragement, just my honest opinion.