No, you can't directly call a method of http.Controller via RPC in Odoo. The RPC protocol in Odoo is used to interact with the models not with controllers. The http.Controller methods are meant to be called via HTTP requests. 

If you need to expose a method to be called via RPC, you need to define it in a model. If the logic you need is currently in a controller method, you might have to refactor your code to move the necessary logic into a model method.

I hope this helps.