Hello and welcome to pudom.
The sample that you listed should be good, I haven't had it but the 7542 is a classic recipe and has been know to make some great puerhs. The number system work as so. . .
1st 2 numbers (75)= date introduced, 1975
2nd number (4)= leaf grade, 1-10, 1 being the best
3rd is the factory code= 1; Kumming, 2; Meng Hai, 3; Xia Guan, 4;Lan Cang, 8; Hai Wan
You do not have to worry about getting a "false" sample from PuerhShop, Jim is a trust worthy dealer. If you have the extra money I highly recommend this cake,
http://www.puerhshop.com/index.php?main ... cts_id=153
It is excellent for beginners, well priced. It may just be me, but if brewed correctly I dont know how anyone could not like this tea. Its Sweet with hints of fruit, wood and honey. It was my second cake and I couldn't of been happier! Check out my in depth review of it here. If you are not a fan of really strong tea I would probably stay away from blends right now as they are made for aging so the flavors can mellow, A 2005 is no where near aged so you may get an unhappy first experience. Thats whats neat about the Jinggu cake, you will not see any of that bitterness.
This cake would also be good. It was my first cake, Although, this one is slightly bitter and smokey and is slightly powerful because this is also a blend that is meant for aging, but you should like it, I did.
http://www.puerhshop.com/index.php?main ... cts_id=191
If you insist on getting a sample This would be a good one
http://www.puerhshop.com/index.php?main ... cts_id=273
This will make you much happier than the 7542.
Good luck and if you have anymore questions dont hesitate to ask!