Delay in I 797B Approval notice for cap subject H1B FY 2015 petition

Hello, My company had applied for an cap subject H1b Petition for FY2015 and the receipt notice was received by Employer on 29th April 2014 ( it was picked in lottery). Also when i check the case status online in USCIS web site, it says on May 2nd 2014 this I129 Petition was approved. However, until this point my employer has not received the I797B approval notice (since employed had requested consular processing). Since its almost been 4 weeks past the last online status update, I wanted to check is 4 weeks an expected time frame for the approval notice to be mailed or the is the delay something I need to worry about. Also can my employer or their attorney enquire with CIS to check on delay? Thanks