Here is a pic of what the new solenoid looks like.
The new ones don't always have the delrin pilot block (middle section). There were some before the delrin was used that had an aluminum pilot block.
The easiest way to tell if you have one of the original solenoids is if the spool block (large red section) has a silver cap on the end of it. If it has the silver cap, then it is one of the originals. If that section is all red and one piece with no silver cap then it's the newer revision.