Inspiron 3020 CPU fan/heatsink backplate question

I posted this question as a reply on another thread, and I believe that I should have asked this as a question in itself (long...bear with me):

Now that I know the motherboard model number (C0YYY, thanks again), has anyone who has removed that motherboard looked at the back, particularly in regard to the backplate (or lack thereof) supporting the heatsink/fan and the CPU mounting bracket?

If there is a backplate, is it fixed in place, or will it come loose if the CPU mounting bracket screws are removed?

The reason I ask: at some point I will need to remove the heatsink/fan assembly (which I will continue to use) and refresh the thermal paste.

While there, I thought I might try installing one of the contact plates by Thermaltake or Thermal Grizzly. I'm not worried about trying to drop temps by a few degrees, but am rather more interested in mitigating warping and inconsistent contact with the IHS. It also makes thermal paste application a bit neater.

The concern: to mount the new contact plate, the CPU mounting bracket must be removed. My fear is that when I remove those four screws, the backplate will fall off and I will have to take out the whole motherboard to retrieve it.

I realize that I could resolve this issue by taking out the motherboard myself and looking, but if I can avoid that by tapping into the Community's knowledge base, so much the better.

Thank you for your patience with this long-winded question, and thank you as always for your help