If I can be of any help to move you in the direction of an expert, the 1521 model number was applied to these machines:
1. Diamond Jubilee 1984-1987 - Sand/Jade (my favorite of this generation, 1968-1994)
2. Marquise 1987-1988 - Taupe/Sand
3. Grand Marquise 1988 - ?? - Sand/Blue
4. Ultralux LX - Sand/Blue
5. Ultralux Legacy - Sand/Blue
6. Ultralux Classic ?? - 1994 - Blue/Sand (my 2nd favorite of this generation)
7. Commemorative Edition 1994 - Chrome/Black (super- rare, employee-only incentive model)
Things get a little tricky with the Grand Marquise and Ultralux machines. All of the Sand/Blue machines (like yours) LOOK the same, but technically they're not all the same models. None of the GM machines had stickers with their names. Some of the Ultralux LX machines had name stickers, some did not. I've not personally seen an Ultralux Legacy sticker, but there could be one. Somewhere there's a thread that talks about which serial numbers and motor wattages relate to which model name, but I can't remember the tread title. Also complicating things, some of the Ultralux models had blue textured metal trim on the top like the GM, and some had silver textured metal trim like the Ultralux Classic.
Fyi... other model numbers for this generation of machine are easier to sort through:
1205 - 1968-1974 - Turquoise/Sand
1205 Golden Jubilee 1974-1975 - Gold/Sand
1401 Super J 1975-1978 - Gold/Sand (slightly longer than the Golden J, noticeable on the "top" cover)
1401 Olympia One 1978-1982 - Brown/Sand
1505 Silverado 1982-1984 - Gray/Light Gray
...then come the 1521 models
1. Diamond Jubilee 1984-1987 - Sand/Jade (my favorite of this generation, 1968-1994)
2. Marquise 1987-1988 - Taupe/Sand
3. Grand Marquise 1988 - ?? - Sand/Blue
4. Ultralux LX - Sand/Blue
5. Ultralux Legacy - Sand/Blue
6. Ultralux Classic ?? - 1994 - Blue/Sand (my 2nd favorite of this generation)
7. Commemorative Edition 1994 - Chrome/Black (super- rare, employee-only incentive model)
Things get a little tricky with the Grand Marquise and Ultralux machines. All of the Sand/Blue machines (like yours) LOOK the same, but technically they're not all the same models. None of the GM machines had stickers with their names. Some of the Ultralux LX machines had name stickers, some did not. I've not personally seen an Ultralux Legacy sticker, but there could be one. Somewhere there's a thread that talks about which serial numbers and motor wattages relate to which model name, but I can't remember the tread title. Also complicating things, some of the Ultralux models had blue textured metal trim on the top like the GM, and some had silver textured metal trim like the Ultralux Classic.
Fyi... other model numbers for this generation of machine are easier to sort through:
1205 - 1968-1974 - Turquoise/Sand
1205 Golden Jubilee 1974-1975 - Gold/Sand
1401 Super J 1975-1978 - Gold/Sand (slightly longer than the Golden J, noticeable on the "top" cover)
1401 Olympia One 1978-1982 - Brown/Sand
1505 Silverado 1982-1984 - Gray/Light Gray
...then come the 1521 models
