My understanding of the term "VIP proof" is that it doesn't refer to a characteristicallly different method of striking, but that they are normal proofs produced in very limited quantities for VIP visitors in years when proofs weren't otherwise issued. Therefore there aren’t any VIP proofs for e.g. 1950 1951 1953, but would exist if struck in 1948 1949 1952 or 1954.