Small Engines (Lawn Mowers, etc.): JD LT155 Valve cover leak, head gasket, jd dealer

Question
I have a situation almost identical to the gentleman in this post:

http://en.allexperts.com/q/Small-Engines-Lawn-1746/Smoke-engine-30-seconds.htm

However I'm fairly certain the smoke is coming from the oil dripping onto the hot muffler and burning off.  That is why it takes about a minute or so to begin smoking because it takes that long for the muffler to get hot.  To me it looks like the oil is leaking where the valve cover bolts onto the cylinder head.  Local JD dealer replaced the head gasket 2 months ago and no leaks until now.  It's been about 3 weeks since I last mowed because of the dry weather.  Ordinarily I mow once a week.  Is it as simple as checking the tightness of the valve cover bolts, or do I need to take the cover off and see what else could be happening.  fyi...they said they sealed it with silicone.

Answer
yea very possible for it to be leaking there you should be able to tighten it it should be a 516 bold two of them just don't break them and them sealing them with silicone was ok but being a customer they should of just put a new gasket in that would be easier for future take off the gasket brand new wouldn't cost you much of anything if you just wanted to try that or just try and tighten it first that would be ok to good luck let me know