Yes that's right, if you coded the credit note to the fixed asset cost account, then your journal would be hitting the fixed asset cost account. The other option is there's a setting (Fixed Assets | Setup | System Setup) where you can allow negative asset cost (which should mean the credit appears as an asset proposal - not 100% sure on this as I've never enabled the setting but I guess you could link them with a common parent, maybe?)
So resulting journals would be (I've included Depn in this example):
Vendor Bill (Nov 2019)
Dr: Computer Hardware - Laptops $360
Cr: Accounts Payable $360
Depreciation (Nov 2019)
Cr: Accumulated Depn - Laptops $10
Dr: Depn Charge - Laptops $10
Depreciation (Dec 2019)
Cr: Accumulated Depn - Laptops $10
Dr: Depn Charge - Laptops $10
Vendor Credit (Dec 2019)
Cr: Computer Hardware - Laptops $360
Dr: Accounts Payable $360
Disposal (Dec 2019)
Cr: Computer Hardware - Laptops $360
Dr: Accumulated Depn - Laptops $20
Dr: Gain/Loss on Disposal of Asset $340
Adjusting entry (Dec 2019)
Cr: Gain/Loss on Disposal of Asset $340
Cr: Depreciation Charge $20
Dr: Computer Hardware - Laptops $360
My adjusting entry above is clearing the depreciation charge too otherwise you end up with a gain on disposal (it gets a bit tricky if your year end was Nov 2019 and you want to be 100% correct in your P&L)