Well, I'm old enough, and I vividly recall that the Bills were actually thought of as a team on the upswing, not universally picked to be in last place in '88.
In 1987, Bruce was first team All-Pro, Conlan was defensive ROTY and 2nd team All-Pro, Bennett was a dynamic addition and I believe runner-up to Conlan for ROTY. Plus the defense had solid players like Bentley, Smerlas, and Talley. The pieces were in place for a dominant defense, which they were in '88.
Offensively, Kelly made his first Pro Bowl in '87. Admittedly the Bills' running game was suspect, with Ronnie Harmon proving he couldn't be an every-down back. Drafting Thomas in '88 was a risk, considering his previous knee injury.
Going into '88, the team had alot of potential, and there was concern whether they could turn the corner and become a playoff team. So, while going 12-4 was somewhat of a surprise, it was not wholly unexpected. And in no way were they universally picked to be last in the division.
A better analogy would be the '99 Rams, who everyone had picked last, especially after Trent Green got hurt in preseason, or the '06 Saints, coming off their disastrous post-Katrina '05 season.