Body number 100317 built the third week of March ????

Yes, it's a modified faked tag.

Isn't March too early for a 4K?

Here's mine (verified by Jerry M)

Late March 4K’s
 

Correct me if I’m wrong but I think there are some known late March 4K’s.

very late. first week in april was the crossover from 4p to 4k

it is not real would have been awesome but defiantly modified. still will keep looking for a L78 67 camaro!

Some of the 67 Yenkos had a dash and some had a dash and a code and some didnt have a dash or a code.

4P?
 

Sean, are you familiar with the 4P that Luzl78 is referring to?

Rich no sir. I am not that great with the camaro's just being honest here. I have seen the 4p before

4P explained
 

First thing first, I don’t claim to be an expert first gen Camaro person. Anyone chime in and correct me if I’m wrong you won’t hurt my feelings. The only 1st Gen cars I’ve ever owned were-are 67’s.
In reference to the L78 cars the first ones had the position 4 of the TT as 4P. That code was already being used for the 350CI cars. I’ve never heard as to why GM did this. Sometime in early April they went to the 4K code as is seen in most L78 cars.
If you see a 4P car don’t absolutely think it’s a small block car because it could be an early L78 car. Of course then you have to compare the vin and build date cross referencing things process.
JoeC explained the dash after the 4K well. I think this TT tag is definitely a poor example of someone trying to fake a 67 Yenko car.