got he heat gun last night and the mag tube is one, wasn't too much caked on locktite but it did take a while to heat it up, maybe i was being overly cautious. i also noticed a slight difference in color, but not that big of a deal. my end cap threaded up with no issues.
thanks everyone for the tips!
Here it is in writing; https://www.benelliusa.com/support/faq The Benelli rep told your people that because they plainly say that it is not safe to shoot slugs thru anything tighter than an IC.
Obviously, lots of people ignore that advice and do it without apparent problems- yet.