I've sometimes seen the model's name listed in editorials ( sometimes it's buried in a caption and sometimes only a first name); and if the model is a superstar you may see her named on the page. I have some vintage 70s magazine where they do a whole feature about a model and give her name on each page like a US Vogue issue about Lauren Hutton.
I've found some 'round-ups' where they get beauty tips from the models and each model is named. Some of the old Cosmopolitans use to do that frequently.
I've never seen advertisements name a model unless it's one of their star models, like a CoverGirl Makeup ad saying, ' our model Christie is wearing...'. Or the Revlon 'Most Beautiful' ads with the models named in each ad.
I've never known how to id models.
Bellazon.com can be a good resource but you have to go hunting.
You can also try a google image search where you load the image itself to see if you can find a match, but that's not always successful.
And sometimes a magazine will do an expose about the modeling industry and you may find info that way also.
Otherwise old model agency books can help ( Ford, Elite, Zoli, Wilhelmina, etc). I've seen those books on eBay but they're very pricey.