Syspreping a previously imaged PC

I’ve recently inherited our SCCM environment. The area I have the least experience in is is the OSD side of things.
 
We image our workstations via PXE boot and task sequence. We also send a pre-staged media image off to Dell so that when our workstations arrive they immediately boot into WinPE, apply our wim image and join the PC to the domain etc.
 
The time has come to update the image that Dell sends out on the workstations. My question is this.
When creating the image to send off to Dell, Is there anything wrong with creating that image by PXE booting the workstation and installing the OS/applications via the task sequence we use for existing workstations, applying all the latest windows updates and then removing the PC from the domain (which was joined during the imaging processes) and then running through the SCCM prestaged media process?
 
In a nut shell, can I sysprep an image that has already gone through the SCCM OSD process/ joined to the domain?
 
The reasoning behind doing this is to only maintain one task sequence. That way, whenever the Dell image needs updating, we freshly image a workstation / apply updates / remove from the domain and then run through the SCCM prestaged media process.
It might be worth mentioning that I’ve gone through the whole process and tested the results. The finished workstation appears fine in all respects. I’m just wondering if I’m doing something that might come back to bite me.  

Hi ,
 
From all the experiences I had with OSD it's always better to create your reference computer with a fresh install ( not from SCCM or anything else )
 
Small tip , install it into a VM on ur laptop / desktop and play with snapshots to always keep your image clean .
 
cheers
 

I think the general concensus is that you want to capture your image using MDT, that's what is/has been preached atleast when I attended the sessions at MMS that pertained to that subject.