Hi gbisaga,
No you cannot, since you may have deleted records. What you can do however is a simple call where for your fields parameter all you pass in is max(RecordID) and that will give you your max recordid, then you can build your query to get all records. Or you can use count(RecordID) to get the count. Simple C# examples below
MethodAPI.Service _MethodAPI = new MethodAPI.Service();
lblMethodAPISelect_XMLV2.Text = _MethodAPI.MethodAPISelect_XMLV2(CompanyAccount, Login, Password, "", "invoice", "max(recordid)", "", "", "", "");
_MethodAPI.Dispose();
MethodAPI.Service _MethodAPI = new MethodAPI.Service();
lblMethodAPISelect_XMLV2.Text = _MethodAPI.MethodAPISelect_XMLV2(CompanyAccount, Login, Password, "", "invoice", "count(recordid)", "", "", "", "");
_MethodAPI.Dispose();
Dave