Thanks for everyone's reply,
According to Canfield's book on page 799; 200,000 to 500,000 should be a short pinion with a spanner and windage knurled with elevation checkered.
500,000 up should be a rounded bar, windage knurled, elevation checkered.
At 472,182 this may be correct?
None the less, thanks for looking and your thoughts.
Regards,
Tom