From my investigations, it would appear the badges are near identical, but the OEM CT1 badges have a bow manufactured into them.

Does anyone have any to hand to compare?

You are correct. CT is bowed and JT is flat. (and warped in my example)
 

That's what one of the experts, DEET, has posted on the forum here. 

I have a set of JT1 badges and they are flat.  I have used CT badges and they are slightly curved. 

I bought the JT badges because they were cheap and available...  I'm pretty sure PeteRT1 used the same JT badges on his CT...  I haven't installed mine...  bought them because they were becoming rare and I may need them in the future.    

It seems it would easy to use JT badges on a CT tank and maybe just stick a square piece of double sided tape on center backside of the badge to force a slight bow.

Not sure how you could flatten a CT badge for the JT tank. 

In my opinion, the only way to know if the badges you are making will work on a JT is to try it on a JT.
My research says the only difference is the bow. So does that mean that the CT badge is slightly longer? The mounting hole distance shorter?

I would find someone in the UK that has a JT and go try YOUR badge. 

If you want, you could send a couple over to me and I'll evaluate them. The pictures look promising, but that can only tell so much.


My email: This email address is being protected from spambots. You need JavaScript enabled to view it.
 

Thankyou all for taking the time to reply. As anticipated I have a lot of JT1 and HT1 guys in the US asking if these will fit their badges. DEET - Give me a week to try locate someone closer, if not, I'll fire one over to you.

So if you are in the UK, and have a JT1 or HT1 tank, and would like to be the guinea pig, please get in touch!

Now this is really amusing (yes, honestly!).

There is an existing thread here on my CT1C coming to me fitted with a tank from a HT1. I've just popped out to the garage to see what the badges are like and bu**er me if they aren't the curved ones, presumably meant for a CT1! 

Anyway, let me know if you need any info etc (I'm in the UK). 

Alan, you are the perfect guinea pig.

Mark, you are quite right the badges on my CT1-C are the JT1 badges.
  

I tested them out this afternoon, they worked great
 

Excellent, I'll be in touch and perhaps we can arrange a test fit on your HT1 tank. Blimey what a game.

"Excellent, I'll be in touch and perhaps we can arrange a test fit on your HT1 tank."

Yes, that should be fine.