Does the suffix L after a number always have the same effect as placing a parenthesis with "long" in it before the number?

Does the suffix L after a number always have the same effect as placing a
parenthesis with "long" in it before the number?

For instance, suppose int is 32 bits, is the type of 0xffffffffL really long?
The type of 0xffffffff is unsigned int, so I guess 0xffffffffL is unsigned
long rather than signed long.
Does it depend on whether long is 32 or 64 bits?