All blades have Oster 76 labelling (Oster 76 is the US version of the Oster 97) this is normal and all original Oster 97 blades being sold in the UK should have the Oster 76 labelling as all Oster products are shipped in from the USA.
 
Sizes available in:

00000 = 0.2mm

0000 = 0.25mm,

000 = 0.5mm,

0A = 1.2mm,

1 = 2.4mm,

1A = 3.2mm,

1½ = 4mm,

2 = 6.6mm

3½ = 9.5mm