Not to be poking around in any super secret secrets, but is there a possibility that the lettering on this sign could represent something Masonic? I am not a Mason so I don't know, but maybe someone here does. Just a thought, continuing to think on this.
Also - as I have subsequently discovered, if in fact this was the original Rupp homestead (i.e. that of George Rupp Sr), he died with no will so the estate was not entirely settled until 1816. His son Herman was responsible for the settlement and inventory etc, and I'm currently *assuming* that Herman was in control of the house/property until the settlement. Given that 1817 was the following year, and that (1) Andrew was up in Weisenberg twp at this point, (2) George Jr was unaccounted for to the best of my knowledge with any certainty, (3) Johannes/John was dead, and (4) Herman was still there in Macungie, I'm going to go out on a limb and believe that Herman had been living in the house or on the large property, and once the estate was settled, he passed it on to his only son Jacob. This is speculation.
Meanwhile back to the Masonic thing: From Roberts et al
History of Lehigh County Pennsylvania, and thus unverified but perhaps a starting point:
"Jordan" was also the name of a church and congregation between Allentown and the Macungie area, just a few miles space as I understand it, so
could it be possible that when the lodge charter was granted in 1817, Jacob Rupp was in possession of the home and it was being used as a Masonic lodge? Again, I'm not a Mason so if this seems silly, please forgive me. Just thinking out loud.