Most of the animals were onshow, yes. The only ones missing, as I recall, were the scimitar-horned oryxes, American bison, cape buffaloes, congo buffaloes, fallow deer and ostriches. Knowsley had reduced the entry price due to some of the animals being offshow, which I thought was very decent of them.
A long time since I saw a shot of a fully mature 'blue' Nilgai bull. Whipsnade's appear almost to have disappeared, while Howletts seem only to have females. Best groups in the UK now seem to be at West Midlands & Knowsley.