Green’s Dictionary of Slang

tops n.2

[the predicted side rolls to the top]

(gambling) doctored dice used for cheating purposes.

[US]C. Coe Hooch! 87: Take that out an’ buy yourself a set o’ tops.
[US]‘Goat’ Laven Rough Stuff 136: These phoney dice are called ‘tops.’.
[US]Goldin et al. DAUL 224/2: Tops. Crudely loaded dice, capable of being used only upon the most gullible of victims. [Note: Tops are manipulated in and out of play by the swindlers. They are so weighted as to guarantee the turning up of a single combination of numbers.].

In compounds

tops and bottoms (n.)

1. fake gemstones, with a very thin layer of the genuine jewel stuck on top .

[UK]F.D. Sharpe Sharpe of the Flying Squad 282: ‘Tops and Bottoms’ are another means of making easy money [...] They are fake stones with real tops stuck on. A very thin layer of real emerald or diamond, for instance, is glued to the top of a big piece of similarly shaped imitation stone.

2. (US gambling) crooked dice.

[US]V.W. Saul ‘Vocab. of Bums’ in AS IV:5 345: Tops and bottoms — Mis-spotted dice.
[US]A.J. Pollock Und. Speaks.
[US]J. Scarne Complete Guide to Gambling 693: Tops and bottoms – gaffed dice which bear only 3 different numbers on each die.

3. (UK Und.) a roll of money with large denomination notes visible at the the top and bottom but blank paper, trimmed to size, in between.

[UK]J. Gosling Ghost Squad 53: In his pockets were bundles of ‘tops and bottoms’ — rolls of ‘notes’ with genuine fivers on top and bottom and sheets of toilet paper [...] their edges trimmed to look like notes, in between.