Bpinder, You need to learn a little about Phillips manufacturing codes (Amperex, Mullard, Valvo, Seimens, etc.) that are etched into the glass of the tubes. The codes will tell you tube type and where and when they were made. Here is a link to a pdf file that will tell you all about them:
http://eastwoodamps.com/PhilipsCodes.pdf
The Tubemonger website: http://www.tubemonger.com/
has a very extensive library of pictures of tubes. There is a link to the library on the left side of the homepage. Have fun!