So, for starters, many girls nowadays have their OF run by managers. As such, if you send a dick pic, it will likely be seen first (and perhaps exclusively) by some guy pretending to be the model.
I've never asked for a dick rate myself, but have seen the price lists of many models. The cheapest type of rate consists of just writing a number from 1 to 10 or a text message. However, it may be the manager who does this, because you have no way of knowing whether the model actually saw it and wrote the message.
Another type is a voice message, but unless you know other people who bought dick rates from the same model, you can't know whether she did it just for you or sends the same one to everyone who asks.
I'd say the only way you can be sure is if you ask the model to make a video rating your dick and showing the pic to confirm she's seeing it. It'll probably be the most expensive type you can order. If she refuses to do it, then yeah, it was probably going to be a premade video or a manager writing a message.