You will be fine rangeron33s, I have done head gaskets with and without sealant, never did find that one way was better than the other, 35 years of head gaskets, starting with a Super Hurricane Flathead 6, and ending with Ford 4.0l a month ago, I did use sealant on that one because friend didn't want to pay for machining the heads.
Don't sweat it, if you blow a head gasket it WILL NOT be from a sealant issue.
Service manuals are guides, they are right more than they are wrong but they are wrong in some statements they make.
The head gasket sealant would be one of those times.
And grain of salt, service manuals are written with a "blank check don't care how much time it takes" mentality, surprised it doesn't say to surface the heads and block before installing head gasket.
My '92 had a 2.9l and I did the heads twice, both times with sealant, first time I had a cracked head, not a head gasket issue.
Second time was after I gave it to my son to drive and got my '94, he overheated it quite a few times because he didn't want the few days of down time for me to fix the water pump, lol.
Never a sealant issue.