I see you are working on a Series II, I will assume it is an L-36. If so, have you read the article in Techinfo? http://www.bonnevilleclub.com/forum/...e=article&k=38
The side rails in the engine block were changed to add locating holes for the rail seals under the LIM in mid-year '97, but the newer gaskets with pins can be used on the earlier L-36 with no problems, the pins just hang out over the side.
You mention you did the uppers, but there is only one UIM gasket under the upper intake manifold on an L-36. Not exactly sure what you are referring to here, but if you read the article above, it will fill you in the fixes you need to do for an L-36.
If you are draining the coolant anyway, I would suggest you do not refill with Dex, instead use "mixes with any type or color" coolant. When you refill the coolant, follow this procedure to minimize trapped air. http://www.bonnevilleclub.com/forum/...=article&k=100