Mstanglx,
You do need to engine to mount the engine mounts before you cover which is easier, but it can be done later, you just will havfe a tougher time getting the blind nuts in. The rest can be down without servos,receiver and such
Just a hint. Take your time and read the instructions for each step carefully. Dry fit everything before putting glue to it. SIG makes great kits which are easy to do.
There is a huge thread on doing the 4*40 which is basically the same plane with the exception of the 40 comes with a single wing servo versus the 60's 2 servos.
Here is the thread
http://www.rcuniverse.com/forum/m_18..._Swager/tm.htm