A surveyor will help you identify soft spots and any delimitation issues on this deck. You can test a bit yourself by walking the decks in bare feet and feeling for movement or listening for cracking/clicking. An easy trick (if you have permission and some time) is to wet the deck and wait for it to dry. Areas that remain wet around seems or bungs indicate the seam or screw area is holding water.
Generally speaking all 80's (CHB or otherwise) trawlers have screwed down teak decks and will fail. Core materials vary from tiny squares of luan as "filler" to marine plywood.
Replacement is inevitable and DIY possible if you're handy and brave. Expensive if you're not. I'm facing this with my boat deck and plan to DIY it next season. Great resources online for repairs and replacement. Here are a few of my favorites:
For us we used this and other survey information to reduce the price we paid to acquire our trawler but know that those dollars were not "saved" as they will eventually be spent for repairs and refits.
I'm a hand guy so this didn't concern me and the boat had been covered most of its life (and still is) limiting severe downstream damage.
I guess my generic advice is:
1. Get a survey
2. Determine what is a deal breaker for you, your budget and your skills.
3. Find the right boat