What struck me was that Albrecht seems to have not been very successful after leaving the Sun Tavern in 1771 and setting up shop in Lititz. Or at least that appears to be so due to the lack of identifiable rifles by him. From Scott's paper I learned that Albrecht was supposed to have help getting business funneled his way by William Henry in Pittsburgh, which never panned out. But he did have some pretty stiff competition from not a few established and successful gun stockers in Lancaster.
I'm guessing that after having been out of the rifle building business for an extended period of time in the 1760's, his notoriety as a gunsmith had faded and I'm sure that the remoteness of Christiansbrunn from Lancaster may have helped to erase his fame. That's just my speculation though.
I suspect that it was the "stiff competition," as you say, from nearby gunsmiths that made it a challenge for Albrecht to set himself up as a gunsmith in Lancaster County and led Moravian authorities try to solve the problem of what they called his "lack of work."
I don't know that he had any "fame" as a gunsmith when he had been at Christiansbrunn. Except for one Shawnee, who recalled in 1754 that Albrecht had stocked a gun for him in 1752, no evidence indicates that anybody knew who Albrecht was or could tell his work from anybody else's work. We know now that he was a master gunsmith, a stand-out among his peers, but did people think that then? I myself doubt it.
Maybe, if he did make the stock of the rifle that has the signed "ALBRECHT" barrel, he adjusted his "style" to tailor his products to the tough new market he found himself in in Lancaster County? Speculation. But possible. I think it's more likely that, as Mike Briggs suggested, it's a barrel that Albrecht proofed in somebody else's stock.
Remember, too, that since his arrival in America in 1750 Albrecht had never had to worry about "marketing" his products. He worked in a managed economy in Bethlehem and Christiansbrunn that supplied all his needs (food, clothing, housing); he did not sell his own work or earn any money from it. That wasn't the case in Lititz and he struggled.