Mike,
The "Prince II" bag on your one Royal is a replacement bag, because the fan case design suggests a March 1985 or older build... back to 1971 even. Your machine would've been made from 1971 to 1975 if the motor rating reads 400 watts, from 1975 to 1980 if it's 3 amps, or 4.5 amps if it was made from 1980 to 1985. Therefore, what is the serial number on this machine? Example: B85-D-74801.
My 1985 Royal 880 (branded Stark Deluxe) was made in February of that year, and it has that kind of fan case.
Regarding your other Royal Prince upright (tan bag/red trim), that is either a model 786 or 787, and along with the baby-blue Prince II model 870, was produced from 1986 to 1990.
Your other blue Royal upright in that picture appears to be a model 604 or 881. If it is a 604, it was made in September 1986 (date code begins with "I86").
Thank you,
Ben
