Group L type issued for two of us is valid to enter China without a stamp by Chinese Embassy?

We are Australian citizens. We two persons have applied Group L type for 2 persons and one company in Sydney is issuing us Group L type on one paper for 2 persons. I have been told by this company that we do not need to stamp visa on our passports in Australia. But we can travel to PRC on that Group L type and condition is two persons are travelling together. Group L type is issued by Bureau of Exit & Entry Administration Ministry of Public Security Peoples's Republic of China.

Is this Group L type is valid? Are we allowed to enter China without stamp on our individual passport? We are going on holidays for 17 days and we do not want that we are not allowed to enter in China. Will you please let me know about this question?
Regards
Shailendra Shah,
Melbourne, Australia.