Reading all the comments, I don't think there is a clear answer but considerable more confusion.
My thread on this is that a lot of people saw and loved a replica or original verison of a HL500 and fell in love with it. I'm sure at the time they didn't recognise the essential points of the bike that made up the HL500. I get excited with anything that looks different and the replica versions of the HL500 allows me to have that, and I can claim it as a "works" bike because its my version and even if you have one its a bet its different to mine.
I have several original bikes in my stable that are just that and I wouldn't dream of modifying them. I wouldn't modify anything original so the HL500 allows me to experiment. I'm not interested in building and exact copy of the original HL500! But its nice being able to get close using the GMC kit. Reading the dramas forum members have had with purchasing the C&J frames we are very lucky.
Two things come out of this for me.
1. I'll never buy an original if it came up because I wouldn't be sure it was.
2. I'll call my example something else, like an AT540 enduro and then have an original that no one else has. But knowing my luck someone will see a picture of it and build it and so the debat continues!!