I'm disinclined to replace things simply for the sake of replacing them, especially if the things being replaced are expensive, reliable and well regarded parts. 150Ds are hermetically sealed solid tantalum caps and pretty bulletproof. (And also, based on a quick search, seem to start at about $5/pop for small ones, and quickly head up to $15-25 or more/ea for larger ones. These aren't el cheapo floor sweeping electrolytics.)
I'll second what others have said - baseline the instrument before doing anything to it. After testing, if it's out, try the factory alignment procedure and see if that improves the performance. If you just dive in and start shotgunning parts, you won't know if you've improved it or buggered it up worse. HP gear from that era was built to last, and unlike consumer products they typically used high quality parts, rather than whatever was cheapest that week.
FWIW
-Pat