Worthwhile? Oh, yes.
Firepower! , I'm aware that you have a number of full-auto firarms, but I don't know if you're more of a collector or shooter.
You're probably aware of the differences in the various models of the Thompson Submachine Gun. In case you're not, the two most common types are the Model 1928 series and the M1 series. The '28 has the actuator (bolt handle) on top, while the M1 and M1A1 have it on the right side. The '28s are usually more nicely made, with better finish and more finely machined parts. Buttstock is push-button removeable, the barrel is usually finned, and there is frequently a Cutts Compensator fitted. A nice Lyman adjustable sight is common. The fore end may be a vertical pistol grip or a horizontal type. Late-production '28s may be have the dull phosphate (Parkerized) finish, a smooth barrel with or without compensatror, and a simple L-shaped rear sight. A 1928 may have been produced for the civil market OR the military.
The M1 and M1A1 were introduced during WWII to speed production. They were originally all military guns, but many hit the civilian market after WWII and the Korean War. The machining and finish appear much cruder, buttstock is bolted in place, barrel is smooth, and there's no comp. The fixed rear sight and horizontal foreend are standard.
On the US market, a '28 model in decent condition usually demands a FAR higher price than a decent M1-type. The latter have greatly climbed in value in recent years, though.
Far less common Thompson Guns are the Model 1921 and the 1927 semiautomatic carbine. Their scarcity leads to much greater value. The original, short-barrel 1927 should not be confused with the late prodction guns from the 1970s and afterward.
The US market is ruled by the fact that no machine gun of any marque not registered before May 1986 may be legally transferred to a private individual. This very finite number of full auto guns ensures that the buying/selling prices just keep on climbing. No matter that a huge stash of collectors' item machine guns is located somewhere, they may not be sold on the open market in the US, even without regard to other import restrictions.
Frankly, I have no idea of the value of a TSMG outside the US. You must be aware that there are few places where a private individual may own machine guns. From your earlier posts, I know you have, or have had, some other very valuable full auto items. In MY mind, a TSMG in good condition would be worth more money than several Kalashnikovs. At around $250 USD each, one --or several-- would be a great buy. Understand, though, that this is the viewpoint of a sport shooter or collector. The TSMG is/was a first generation SMG. Thompsons are compllicated (compared to an AK or Sten Gun,) very heavy to carry in the field, and demand significant maintenance. Several other full-auto arms are far more suitable for combat use in today's world.
All the above is based upon the available guns being genuine, US-produced Thompson Guns. Firepower!, I hope my over-simplified remarks are not offensive to you.
Best regards
Johnny
Words escape me. Why?