Mac 239 brush under old number system?

[Debjo1]

I swapped for a Mac 239 shader brush... didn't know it was under the "old number system".
This brush has MAC 21 on the handle and also it is made in france.. it is black with brown/tan hairs... This is the link to the pic. the brush I have is on the far right.
Is this an authentic brush... does anyone know anything about the 'old numbering system"?

http://www.makeupalley.com/swap/detail.asp?id=3662890

Thanks a lot
Deb

 

[caffn8me]

It looks authentic but I can't confirm that the number is correct. It's from a time before M·A·C fakes were common. I'd be very surprised if it was fake looking at it as the font style and construction are absolutely correct for an old numered brush (I have a couple)