Far as I can figure , yours s a THIRD series . How many of the earlier four versions were differant / , good question ! .

First had lapped iron piston , and siezed a bit often in good ole U S A Summers , or the ( then ) usual close tolerance
hardened linerm took forever to run in fully . So openingem up early , they locked up .Seeing most people put them
straight in a plane and flew them .
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UNLIKELY its a SINGLE RING . ?
The two ring has the shorter rod . ( same as 51 & first 60 , single ring rods , theres two ' fits '  51 & 60 , maybe the 56 is the 51 one .)

EARLY 60s & 46's had thinner liners , larger / smaller case bore , to fit . The 56 would be similar perhaps .
The Dual ring being the one with the thinner liner .

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Got parts catalouges  , but not currently accessable . From Memory , the 56 parts swap out , B B to P B , bar where obvious ,
Im told the 56 & 60 run differant head bolt pitch circles . Wider head bolt pattern on 60s .

As Super Tigre might vary specs between runs , mikeing up ( Virneer ) check / comparison , even for the " right Part " is adviseable .
sometimes some people put production line reject parts , in the ' spares ' packets , on odd occasions . also .