The rough formed tubes were paired and wired together by the Belgian maker, and it is very difficult to 'read' the pattern of those tube.



The U.S. makers had to trust the fella doing the pairing, and proceed with joining, fitting and finishing, at which point the pattern is obvious.

It has been suggested that guns with mismatched patterns were salesmen's samples. I've never seen proof thereof, and we know that at least Remington salesmen carried sample segments



It's not at all uncommon to see a slight difference in crolle patterns.
This is a Husqvarna 49 with different 2 Iron patterns refinished by Mark Beasland



Different patterns are less common, but happen.
A Husqvarna 43 with "Washington" and a crolle



I think this is Bro. Tom's No. 2 Smith with Twist and crolle



And this is an Ithaca with one fluid steel and one crolle tube!