Steve is correct. There are a few pre- and post-98 differences, but the fastest way to determine which era is the number of holes in the side. Pre-98 reels only have 6 holes, as the G2 pictured here. And I cannot believe these are both still available. Everyone who casts 2-4 wt and 5-6 wt must be offline.
I am always on the lookout for a Pre 98 or 94 G-1. I have lost a couple on bids on the big auction but I keep looking. I have 10 other G's in size 2-5, however and they are my "go to" reels in most cases. I use them on rods from 5-7 and on switch rods. They are definitely bulletproof. I bought my first in 1991 and have been steadily picking up more through the years.