PAT Roster -- The 4000s

[Kenneth and Tracie Josephson]

Here are some questions about the 4000 series PCcs from a fellow
Pittsburgh fan who doesn't belong to this list. I hope someone has an
answer:

Wondering if you could pick some brains to confirm the following list of
4000 
series car origins...
4000/1702, 4001/1720, 4002/1740, 4003/1731, 4004/1739, 4005/1729,
4006/1709,
4007/1719, 4008/1767, 4009/1700, 4010/1757, 4011/1733, 4012/4000/1702
As for rehab dates, I have
4001-4007 (PAT 1981-1988), 4008-4009 (PAT 1990), 4010 (Blaw Knox 1985),
4011 (Pitt. Rail Car 1985), 4012 (Ex-4000, renumbered 1986).
Is this summary correct? Numbering scheme of 4000s seems to be out of
sync 
with chronology of rebuilds. Why? 

Any help would be warmly appreciated. 
Thanks again,
R.