Since Perl 3 was released in October 1989 (see Perl and Perl timeline), I don't believe brian_d_foy could have been a Perl 3 user because, according to this 2005 perl.com article, he began using Perl while studying nuclear physics in grad school. I guess that was around 1995 or so because he mentioned in the article that he bought Programming Perl and Learning Perl in the same week! And these books were not published until 1991 and 1993 respectively. Curiously, brian still has the receipts for the purchase of these classic books. :)

I suppose we might find the mysterious dd-b lurking among the 205 Perl 3 users who voted for Perl here:

• comp.lang.perl has passed by 205 to 7 (Dec 1989)

Surprisingly, merlyn voted against Perl back then! The reason for his eccentric vote is explained here.

Update: Unfortunately, brian's Learning Perl receipt, mentioned in the 2005 perl.com article, is today a broken link and the 2005 Wayback Machine version of the article retrieves the text namely:

This is a receipt for the first Learning Perl book I bought. At the time I was working at Brookhaven National Lab, and it looks like I drove out to Stony Brook, probably to go to a sandwich shop that I liked (very little is around Brookhaven). On the way I picked up the Pink Llama.

but not the graphic of the receipt itself (the price, $24.95, is in the title, but not the date). So the date of purchase remains a mystery.

Further Update: Woo-hoo, the graphic of the $29.95 receipt for "Programming Perl" is visible! It was bought from Clerk No. 28 at Barnes & Noble, Auburn MA, on Saturday the 24th of June 1995 at 1:45 pm! brian's description: "I bought Programming Perl at the Barnes & Noble on Route 12 in Auburn, MA. I'd take any excuse to get out of Worcester."

Update: See also: How long have you been using Perl? (no reply from brian_d_foy ... but I like TimToady's response :) Oh, another classic Tim Toady response ... though I love the response to Tim even more :)