Old style or new style. The earlier 1300's had few "upgrades" available. Side saddle, butt stock ammo carrier, some stock options. IMHO the 1200/1300 series of shotguns were some of the best pump guns ever made. Damn strong, reliable, just not a lot of accessories available. The Mossy's and 870's have more of a mainstream following. For me, the Winchester pump guns will always be in my inventory.
A side saddle to carry more ammo and possibly a sling and you should be good to go. Maybe a light mount and light too.
I bought a Specter Gear Winchester 1300/FN Police Buttstock Shell Holder with Rear Adapter for a few bucks on eBay. It holds 6 shells. No too many upgrades but it is strictly a self-defense shotgun.
Are you sure it is a defender because in this pic it looks like a regular 1300 the defender holds 9 shells
That is not a "Defender" in my mind. It is a nice Winchester shotgun with standard (5 shot) mag tube. I believe Choate makes mag extensions for them. A side saddle and/or a buttstock ammo carrier and a couple cases of ammo will round it our nicely. Nothing wrong with the wood. It could be died/stained darker if you chose to.