Numbers on spkr. The one ending -11 is what RCA calls a drawing
number. There was a cross reference to get the real 6 digit
part number. The one starting 274. 274 is RCA's EIA number.
Almost every US mfg had a different one. The 6505 is probably
the date code. So 1965 fifth week. Last number probably run number
for that week.
Common impedance for speakers was 4-8-16 & 32. It is not DC
ohms & will measure different. Matching impedance to the design
is most efficient & safest. IIRC Sams shows actual impedance.
Try to match it. Also be sure there is no DC voltage on the speaker
wires before replacing it. Compare to the good channel. A leaky
output can pop the spkr or other things....
73 Zeno
LFOD !