Right now, unless they are looted from a museum or a collector’s vault, including such would be unrealistic and not really possible with the tools the MC has available.
For example: Making one medieval 16th century breastplate takes 35+ pounds of high-grade steel, a process that itself takes over a week to produce, using a back-yard forge of the type even remotely possible. Then it takes another week to actually make that breastplate using power-hammers and other modern tools that might not be useable in the MC’s world due to power issues.
Once we actually find a safe haven of some sort and can build proper infrastructure, this would be a more viable thing.
Also remember, while the best armor of the day was able to reflect musket projectiles of the 16th century, today’s armor piercing bullets and higher caliber ammunition would still punch through that armor.
Maybe we’ll be able to find some collector’s stash somewhere though for a ready-made stock-pile. Lots of crazy Coloradans in the “Mile High” state