Yeah you’re probably right. They’ve made it 30 odd years so far like this and they’re tensioned up lovely. A good clean up for them today then is in order.Leave as 2X, i have some two cross, you have DT DB spokes there too. There was a period of 3x/2x Rears (or people would take it further if building yourself 3x / radial rear.)
Be plenty strong and all the wear and tear is bedded in to that setup.
That and you'll need to stretch the spokes by 6mm