I can try using a piece of mirror similier thing to it since the original reflectors have been removed.Maybe this will work. With similar parts detection was reliable at 10 ft. Tx IR LED is no part number, CAT #
ILED-13 from All Electronics, 940 nm, 60 ma continuous, 1A pk., 5 mm., 16 deg. From Digi-Key a match to
OPL550-OCA is SFH4545, 10 deg. or TSAL6100 but are not 5 mm packages.The mounting is as shown in post by ducey01. I found a shorter focal length plastic tens at Ace Hardware 3 cm dia., 5 mm fl. but not tried yet. At 5 v, buzzer might not be loud enough but rower availability has not ben established.
A red multi faceted reflector was tried with boor results, but a piece of shiny beer can worked as a first surface mirror for testing.View attachment 149761