If you want to keep 87 in it thats fine, but i’d start putting 93 in it soon!
Your right, only flat tappets need broke in, rollers do not. Mostly b/c the cam is “scrapping” the tappet and also the lifter rotates around in the galley when rollers do not. So your good to go.
Lastly, idling the car is the worst thing you can do. That 20" of vacuum is sucking hard on the rings when instead you want less vacuum to help seal them. If you let that motor sit there and idle for like 20min, it would smoke the rest of its life. Definitly get it ready, go drive it or something!