Yes. The first is a module that runs the listed submodules in order.
The second is just a plain python list of submodules.
If you do
stage1 = nn.Sequential(*list(pretrained_net.children())[:-4])

then you can do
output = stage1(input)

but if you didn’t use nn.Sequential, then you would have to use a for loop
temp = input
for module in stage1:
    temp = module(temp)
output = temp