Quick,
If it is really a "HT" it is a newer model. Even though the original H&R started using serial numbers in 1940 starting with the letter "A", they never went past "AY" used in 1982.
I currently have two lower pressure barrels on shotgun receivers, a .45/70 and a .357 Mag.
I think H&R would have stopped making rifle barrels for the shotgun actions if there was a problem with the receivers. After all, they started Topper rifle production at least as early as the 1950's, so there has been plenty of time for problems to have manifested themselves.