Answering question for Vacuum Tube - 6V6-SD-M, Groove Tubes, Matched Pair

Product:
Vacuum Tube - 6V6-SD-M, Groove Tubes, Matched Pair

Question:
I have deluxe reverb 65 --just need the matched 6v6 tubes on the old tubes both had a marking of BBm -not sure what that means. What do yo suggest? I am used to TAD tubes and always had good luck with them