The Original Le Trap was created and designed by Jay LeTrap (sp?) (Sorry Jay it has been decades) as was the LeTrap "Square" gold pan. Jay was (if memory serves) from the USA and linked up with Del and Doris Walters - the owners of Bedrock Supply in Edmonton Canada. The original mold for square pan and the sluice were brought to Edmonton and there were some refinements on it though a big part of early production focused on getting the right plastic formulation that would properly hold up to use and would form properly to the mold. We spent a lot of time researching and testing before we got it all to work. I was involved with Del during early testing of the designs and in the product development as well as field testing the products. After Doris and then Del died things changed at Bedrock and the company made the decision to sell the LeTrap rights to JOBE. After that I lost track though still use the LeTrap sluice and pan to this day.
The design had several features that were felt to be important- these would include the pinch and the flare as well as a strange lip along one side and not the other which was there so you could turn the sluice on its side and use the lip as a trough to wash the cons out easier.
I cannot comment on the newer iteration on the design without actually seeing and playing with one but so long as the critical design of the step and the drop riffle were kept you could probably make changes to length and flare and still have a great gold catcher. The very first River Robbers were black plastic but Bedrock switched to green in the early design process so if you come across an older black one I guess it is now Vintage, just like those of us who first played with them.
