I have never seriously started any collection of vintage Tudor until recently. With the increasing prices of the Rolex Sports models, the Tudor ranger seems like a good option especially when one can still find the Tudor with dial in perfect condition.
I have read in many forum that there are many fake Tudor Prince around. As such, one has to be be extra alert when collecting by ensuring the model number correspond to the Tudor Prince series..
I have checked across the web and found that Tudor Ref 9050 and 90520 are normal Prince Oysterdate models.
According to the web: http://masasima.hp.infoseek.co.jp/mywatch/rolexspec.htm
Tudor Ranger models are: 7992, 7984, 7934, 7964, 7990, 7963, 7966/0, 90330, 90020 and 90220.