I think it's worth stepping back and taking a broad-perspective view of the GSXR400 and Bandit 400.
As far as I can determine (from researching these 400cc bikes on the interwebs) they were never involved in a factory-supported racing effort. While many of the design features that went into the GSXR's construction were actually developed on Suzuki racing motorcycles, there was no ongoing factory engine development effort that centered on racing a motorcycle with this 400cc engine. Instead, the GSXR400 and the Bandit 400 were just "volume-sales" models which were meant to contribute to the manufacturer's bottom line profit and this situation even includes the very racy-looking Special Performance (SP) models of the GSXR400.
I'm not saying that GSXR400s weren't raced, because they obviously were raced by non-factory teams (human beings will race anything that moves), and it seems that the GSXR400 was the cream of the crop when 400s were raced because it was lightweight and could be modified with aftermarket parts to produce 67 hp.
But the specifications for a stock, right off the assembly line GSXR400 were focused on meeting other criteria with the major guiding force in GSXR400 and Bandit 400 engine design being the Japanese 3-tiered motorcycle licensing system, which imposed a 59 hp limit for engines up to 400cc (which is why the GSXR400 and Bandit 400 engine is actually 398cc).
It was the necessity of adhering to this 59 hp limit that kept the factory-spec, stock GSXR400's engine internal parts in a pretty static state until the limit was revised down to 53 hp which caused the 1993 models to be de-tuned (mostly by reducing the camshaft profile).
Bottom line: what I'm trying to point out is that pre-1993 GSXR400s and Bandit 400s all came off the production line with camshafts designed to meet the 59 hp limit (I'm sure there were was probably an allowable plus or minus horsepower factor that the Japanese government might have allowed and Suzuki might have exploited that, but nothing too extreme).
So there may be some very minor variation in the camshaft profile (tiny differences in lift or duration), but overall they were set up for 59 hp.
If you wanted to make a real, noticeable difference in the Bandit's engine with a camshaft change you'd probably have to find aftermarket performance camshafts (plus some really high-quality springs to keep the new camshafts from floating the valves at high rpm).