I have two 6L6 tubes in my Allen Old Flame head that I thought were RCA Blackplates. They are stamped RCA on the side of the tube and they are short bottle tube. I was going to order some TADs to have as backups but their site (and an email to them) seem to confirm that the Phillips like longer tube is their RCA blackplate reissue. Allen however is selling their short bottle tube. So I'm confused. Were RCA blackplates short or long bottled?