Because many fly only gyros and / or experimentals, some of the folks on this forum might not be aware that a Standard Airworthiness rotorcraft such as the Bell 47 has strict life limits on many, many parts that cannot be exceeded legally. It's not a suggested TBO as you might find in other contexts but a firm, absolute requirement. It is customary to have a record of the time in service of each of these parts, not just the airframe as a whole, in the logs (the serial number of the part, the date put into service, the time remaining etc., are tracked for each part, with each one having its own data card in the records). For parts large or small, (scissor, gimbal ring, blade grip, bearing, blade, transmission, etc.) you must have a record to show how much life it has remaining. Maximum lifetime depends upon which part it is (1200 hrs, 2500 hrs, etc.). If there is no record, you must overhaul it to start a new clock, or replace it, and some very expensive parts cannot be overhauled (e.g., -47 metal main rotor blades are scrap when the time expires, and the replacement price will stun you with all the zeros). The Franklin engined models are over fifty years old now, and with no records it's scary to think how many critical parts could be way, way over life limit, no matter how nice they look in photos.
You also need to know something about where the aircraft was made if you want to register it in the states. Bell 47s were built under license in Italy and Japan, for example, as well as by Bell the U.S. If you re-import a Bell that once had a U.S. Airworthiness Certificate, it may be possible without too much trouble to get it properly registered with an N-number again. But if it was built overseas by a licensee and was never U.S. registered, you have more hoops to jump through to show it conforms to a U.S. type certificate. That becomes pretty difficult without data plates and such.
I've flown gliders that were certified in Germany and not in the U.S., but registered here as Experimental - Exhibition and Racing. You still need records to import something and fly it in that category here. It's a useful category for former military aircraft that were never civil registered, or for foreign certified aircraft, or for other aircraft that have been modified for racing, etc., but not an end run around the need for original paperwork. You'll also never it get it certified as Experimental Amateur Built, because the FAA is not stupid enough to believe you built 51% of it from scratch.
If you want to rebuild one, you have to have a ship with a data plate to start, or the FAA will consider you an unapproved manufacturer and you'll never get an airworthiness certificate. Bell and the FAA are even getting tougher about doing rebuilds - Bell now makes and publishes records of "destroyed" serial numbers, so if you get a data plate from wreck somewhere without an airframe and try to build a helicopter around it, you won't get that into the air, either.
My guess is that you would never get one of these registered here. As to parts value, you won't be able to use much more than the seat cushions legally without overhaul. I suspect that it wouldn't be worth the cost to truck them up from Guatemala, much less the purchase price.