Blackcat- I think the neurologist is just going to do a detailed exam and then decide if testing for things like muscular dystrophy are warranted. My son is similar in that early motor milestones were normal but then we started noticing things like trouble drawing and not jumping until he was 3.

Polarbear - The OT only did the Beery VMI and the PDMS VMI and grasp. I think she was really only doing a brief intake assessment as a start to working with him. He has done a few sessions with her so far and I think he's figured out how to push her buttons already. He is very defensive and avoidant with motor skills that he finds difficult. DH took him to the last session and said DS just cycled between ignoring instructions, "misunderstanding" instructions, finding a loophole in the instructions, and just lying down and saying he was too tired to continue. DH said the OT stayed professional but was visibly rattled and dismissed him early, so I'm not sure how this relationship will work out.
The OT also recommended PT, but I'm really not sure what that would achieve, and I am internally struggling with the balance between helping him with things that will cause frustration (like writing) and not trying to "fix" everything thereby undermining the message that it's ok to be different. The writing definitely needs work. I know the neurologist and respect her a lot, so I am awaiting her opinion on this.