Does masonry paint affect moncouch render?

[JP_]

Getting a window blocked up and eventually will have the side of house rendered to match the rest of it. In the meantime, can I paint over the blocks with a masonry paint, or is this going to mess up the suckiness of the blocks and make the renderers job harder?

 

[lostinthelight]

I spent a lot of time removing paint so blocks could be rendered so wouldnt be putting any on as a temp measure