Across from Serendipity 3, on East 60th Street, is the Ambassador Terrace, with their lovely 1950s-era (1960s?) vacancy sign. Anyone know what LO stand for? The only LO I could find was for LOuisiana in Canarsie.
Not only did you find an old-style phone number, but the address of Paragon Mutual Investors Service has a pre-ZIP Code zone number, 18. Very rare! Can we assume that it translates into the current 10018? The Broadway address would then put it somewhere between Times Square and Herald Square. Location, location, location!