Yes. They have a higher affinity for certain cell types(ie receptor types) than others. This does not mean it has less affinity than estrogen necessarily. Matter of fact I think it's would be better to assume it still higher, in most cells than estrogen. Saying it can effect bone, pancreatic, prostate, hypothalamic, pituitary, and breast cells with a stronger affinity than estrogem. Now this changes depending on serm and steriods being used. If it is a methylated steriods that can lead to a methyl estrogen it may definitely have a higher affinity than the serm. This is untest here.
However, serms may be are only hope with something like trest. As trest is not reduced by aromatase(no 19nor is) rather is reduced by other enzymes in the liver (
2kvette can explain this much better than I can). . Meaning the AIs cannot do sh!t to prevent estrogen conversion with trest. Which is bad as trest lead a very very potent form of estrogen. So a serm like ralox is the only hope to stop it's negative sides.