727 part throttle down shift questions ?

Can anyone tell me the built date ?

Not an expert but here's what I came up with based on a 10,000 day calendar chart and the 4 digits after the ID number.

1/1/68 = code 2348
2551-2358 = 203
203 days after 1/1/68 (or day 204) = July 22, 1968
Day Numbers for 1968

The first page of this chart of ID numbers doesn't match your number but it's in the ballpark.
http://www.mymopar.com/downloads/transguide.pdf