Flattened primers are not always a sure indicator of overpressure problems, but can give a hint. Sticky bolt lift is a pretty good indication of impending trouble. Are you getting smudged primers? If not, I'd proceed with caution, but not overly concerned. If you are working this load in cooler temps, you may have some bolt lift problems in hotter weather, so be on the lookout for that.
I load my 7mm Rem Mag a good bit over Lyman book spec max, and it shoots great with no problems. Do I advise doing that to anyone? Not at all. Ya gots ta know yer equipment & its tolerances...