Old radios, but reliable! The Nav 121's and 122's still pull a respectable price on Ebay. I like the "component" approach to a panel. If a com radio fails, you don't loose half your nav capabilities while it's in the shop (or vice versa). The ADF and DME are still very useable, and later the space can house a respectable GPS.
Is that ALL the corrosion you found, or just a representative worst example? How old is the paint? It looks like filiform corrosion under the paint, which started at the edges of the metal. Quite common, and easily repairable, if not allowed to progress. Your real worry is where you can't readily see it, such as the wing spars or carry through spars in the cockpit, or stabilizer spar.
The radios give you good capability, but are old, and don't add much to the value. The corrosion (if that's all there is) is light, and not a deal breaker if confined to small areas that can be touched up. Similar corrosion throughout will require stripping, treating, and repainting (big bucks). You do need an impartial mechanic experienced on 150's to do an annual (or at least a detailed pre-buy) before anything is signed or money changes hands. Emphasize your concerns about corrosion.
Are you satisfied with the aircraft's price, history, logbooks, total times, etc.? Have you done your homework and know what to look for?
The folks on this forum have all been through it and will be glad to advise!