It seems that Crankbrothers has made a lot of changes to the Eggbeater line over the years, and they really haven't made any effort in documenting past models. Looking at their site it seems like they'd just as soon forget them rather than try and educate their customers.
The new line goes from 1,2,3, and then the 11 which is Ti.
The old pre-2011 line has names like MXR, C, SC, SL, Ti, 2Ti, 3Ti & 4Ti with the last 4 having more and more Ti parts, right?
There are so many different names and models that it is hard to know which one any given used pedal is at a glance. The reason I bring this up is that I really like Eggbeaters and pick up used and trashed ones from time to time and rebuild them after cleaning them up.
I've got 4 here. I know for sure that the one on the right is a 3 (although the blue plastic tread contacts have been replaced by black ones from a 2 and the blue alloy dust cap has been replaced from a black one from a rebuild kit.
The one that is second from the left is an SL but the blue anodizing on the spring has been removed by my brass brush wheel, along with the CrankBrother's logo on the spindle when I had it fully disassembled. The dust cap is a Ti replacement unit
The pedal on the left used to have a blue anodized spindle but the brass brush cleaned that all off. It was half flaked-off anyhow and looked like kakah. The pedal was and I tried to de-rust it in my oxalic acid dip which only made it turn green and crusty all over. The brass brush cleaned it right up to new looking though. I have no idea what model this one is but I would guess a C maybe. It has a smaller 6mm Allen socket than the more modern pedals
The one the second from the right is a mystery to me. It came to me like this all silver. It has wrench flats on the spindle and the smaller 6mm Allen socket. Also, the ribbed area outboard of the wings is similar to the SL but it isn't squared-off like every other Eggbeater I've seen. It's perfectly round. The body is much more shiny than the brushed surface of the SL. It almost looks chrome plated but there isn't a single chip in it and considering the amount of wear on it I can't believe it could be chromed.
With the popularity of the Eggbeater and other CB pedals like the Candy, Mallet, etc, one would think that there would be a webpage dedicated these pedals and have a bunch of photos and a rundown/history of the pedals over the years since they were introduced. There really is zero resource like this on the web. Maybe Crankbrothers has hit anyone who tried with a cease & desist order, or there just isn't much interest among eggbeater owners.