Thank You for these rare pics!
Here are the 2 APG-27 components I have.
They both have contract dates with the prefix 49- . Curiously the scope doesn't have an Order or Serial # on its tag , and has a Navy stamp.
I've found this on Joe Baugher's site,
" In early 1949, Martin attempted to revive the B-48 program by proposing that the second XB-48 be re-engined with four XT40 turboprops installed in reconfigured nacelles. This converted XB-48 was to have been a prototype for the Martin Model 247-1, an airplane which the contractor insisted was capable of competing with the B-47, B-50, and B-54. The Air Force felt that the contractor's cost and performance estimates were too optimistic, and, in addition, since the XT40 was a Navy-developed engine, it was unlikely that Martin would be able to get enough engines to meet the schedules. Moreover, the Air Force was now of the opinion that turbojets, not turboprops, were the wave of the future for bombers, and on March 31, 1949, Martin was formally notified that the Model 247-1 would not be proceeded with."
Perhaps these were for this second endeavor?