Riser tolerance

[dieselram94]

Hi everyone, I have finishedcleaning off the paint from all the gasket surfaces and laid a straight edge on it and found that a .0025 fealer will fit under the straight edge in one spot on the inner flange of the riser. I have already cleaned up alot of uneveness with a file and rubbing stone. These are GLM manifolds and risers for a 1989 305 gm mercruiser is this an acceptable tolerance? I have two new oem gaskets for it (silver thick gaskets) and I understand they should be installed dry. What is the allowable tolerance?
Thanks everyone.