Serial Number On Block Of 6 On Centenary Birth Of General Sir John Monarch?

Hi all

I have inherited my late grandfathers stamps and now I can say im addicted ;). I have found a block of 6 x 5d centenary birth of general sir john monash and found a serial numer on the block see pic for details. I was curious if this is a rarity to have a serial numer instead of a plate number.

And also does anyone have any idea how much this block with serial number is worth

Would love to hear your thoughts and comments

Thanks

It's the sheet number if I remember correctly.

The gentleman's name is Sir John Monash - could you please edit your post?

Thanks for the reply bobby and the correction.. changes made.

Do u know how much it would be worth? :)

Very little I'm afraid, but could be a nice item in an Australia WWI display

Thanks bobby :)