score:4
Short answer to your question:
Can one easily find highland specialties in the capital ?
Explanation:
Perú is well known, apart from Cuzco, for it's cuisine. There are plenty of local dishes in the diferents regions and you can find most of them in Lima (can't say the same on other cities).
Why in Lima? Because Perú is a centralized country, almost everything is focused on the capital.
Back to your question, you can find the most 'famous' dishes in many restaurants, a quick search on tripadvisor throw me a lot of restaurants, in any case you can ask in your hotel and they will tell you with more details.
Not every restaurant will be a fancy one, so don't worry about that. Also if you go the nearest market it's probably that you will find "el menú del día" (menus day) but it's not sure that you can find the dish you want, you can try your luck anyway.
Upvote:3
I live in Lima, Peru and you can easily find any kind of specialties in Lima from the Andes and also from the jungle.
I would suggest you ask in your hotel and emphasize the fact that you are looking for a normal restaurant and not a top one, also you can go to markets that are on the street where they sell menus for a really cheap price however I doubt you will find cuy in one of those...