The P line did have brazing on the seat cluster,rear drops,canti posts but the main triangle/fork were tig welded. Amazing light race bikes welded with Tom's development with Tange to produce Logic tubing. Back in the day I bought a P23,22,21 they all broke after a year or two of racing off road here in BC. They were made by Tom in small numbers over the years {few hundred} Most that came to Canada didn't survived the only ones I have seen available are in the US and a few in your neck of the woods. If you are interested in a full fillet brazed 1982 Mt Tam in a 19" I have a very rare one in my collection I am considering letting go.