Greetings,
If you are talking about being able to join the 356 Registry with a kit-car, well, yes and no. You can join the Registry without owning any car. But if you join the 356 Registry you would not be able to enter the car in a Registry event. The Registry is for 356s that came off the factory assembly line in Germany.
The whole kit-car replica thing is pretty sensitive to alot of Porsche owners. There are as many opinions as there are people! And not just 356ers. Take a look at a thread on the 997 board about a guy that tricked his 997 out to look just like a GT3 RS. He got ripped for being a "poser".
I had a 55 356 Speedster (a real one) and everytime I got gas or parked it somewhere I was asked if it was a kit. Got a little irritating after awhile!
I don't really care either way, as long as the owner of a kit-car isn't representing it as a real Porsche.
There are kit-car clubs that don't look down there snooty noses like some of the other clubs do. It really should just be about fun, but there are people that think fun requires a full price of admission!