So that neck sealer sitting there for say a few years, does nothing to increase overall tension on that bullet?
When we tested for performance from long term storage, versus accidental extreme exposure, or suspect lots, we found that there are changes in the pull forces but they still typically shoot to the accuracy standards unless the ammo is very damaged.
In terms of the role of brass prep and neck tension, crimp, and sealant, you can hardly detect the effects of long term ammo stored properly, but you can detect ammo stored poorly or over exposed as in containers sitting in the desert sun too long.
If the neck sealants leaked, there were shifts in the stats of the pressure and velocity, but those "failures" were statistical meaning a good share were still at the correct average. If the gas and propellants were very dry due to sealant failure, the velocity goes up regardless of the pull force. If the humidity of the powder charge or gas was high, the ammo slowed regardless of the pulls force.
My advice to individuals is to protect your ammo as much as possible from shocks and water. Pay attention to the humidity (water content) of your powder when loading, and study your neck tension tolerance as well.
Several ammo specs are available on the internet and you can study them if you are interested. They include the QC issues of how we look at neck tension or pull force with respect to brass prep, sealant, and crimp.
Keep in mind, Mil-Spec ammo is not match ammo, but it is still pretty good stuff in my opinion after considering some of the commercial junk. You can do a lot worse than real M193 for example of commercial 55 grain ball ammo.
In terms of plinking, hunting, competition, or defensive context, with the proliferation of things like force-gage arbor seaters, or the AMP Press, it is easy for a reloader to study the overall window of "neck tension" or seating force that matters to their recipe.
When you develop your recipe, play with the neck tension sans sealant at first. See where the level that matters begins and ends, and then introduce sealant and see if the charge needs to be adjusted. Some loads are picky and sensitive, some are very forgiving. YMMV