ISAF Racing Rules of Sailing

2 FAIR SAILING
A boat and her owner shall compete in compliance with recognized principles of sportsmanship and fair play. A boat may be penalized under this rule only if it is clearly established that these principles have been violated. A disqualification under this rule shall not be excluded from the boat's series score.

The pns for the Hobie 17(uni) are based upon boats supposedly sailed in compliance with their Class rules.
These rules include a minimum crew weight of 160lbs.

The pns for the Hobie 17Sport(2-up) are based upon boats sailed with an unknown minimum crew weight because there are no Racing Class rules.
The portsmouth rating only says "2 up".

How do you determine if a boat with no class rules is being sailed in "original One-Design configuration"?

Is it "Fair Sailing" for a 17U with a 160lb crew to race a 17Sport (w/jib) with a 160lb crew?
Or 180lbs?
Or 205lbs?

Is that "Sportsmanship"?