How to tell New 357 from old 357 XP Husky?

[RockyRiver]

I bought a like brand new 357 XP Husky for $350.00 and got another new bar and several new chains. The guy I got it from needed some money quick. My question is How do I know if its A catlytic style or a pre cat muffler and engine.
Also where the decompression button is on my other huskys this one has fiting with a hose coming out of it and routing back to somewhere hidden on the engine, is this a new decompression?

 

[HiOctane]

You should have GREEN oil and caps if you are Etech.Has been introduced in late '03.So if your serial number is greater than #0340XXX,you got Etech.The automatic decompression valve like yours is connected to the crankcase by the tube,this way the valve pops off automatically.