Yes, the Birel chassis is chrome-moly steel. It’s irrelevant anyway since the Birel chassis does not wear out any more quickly than any other chassis.
I’ve raced my current Birel R32 for 2 seasons and it keeps responding to adjustments and turning faster lap times. In fact, I turned my fastest lap ever at IMI just a mont before the end of this season.
My previous chassis was also a Birel (2002) and it was raced a lot over 3 seasons. I was the third owner. It was still quite competitive and won a CSC pole position and several club races before I sold it.
I hope this helps.
BTW, if you’re looking at a 2004 Birel, take a look at mine:
http://www.thecoloradokarter.com/phpBB2/viewtopic.php?t=2729
Charles