You got a basic sum assured (value) at maturity date, from outset, based on contribution level and term. There were also pre-determined Guaranteed Annuity Rates at the contract retirement age.
Regular bonuses were added to the policy and once they were added they couldn't be taken away, if you carried the plan to term.
The investment funds 'behind' the provisions of the guarantees were generally conservative in nature (think cautiously managed/mixed asset with circa 50% bonds).
On top of the basic sum assured and regular bonuses you also could get a final bonus, depending on how the fund did over the period. This would also have to take into consideration the policyholders that were left in the fund and future liabilities/guarrantees to them. In the last 10/15 years companies moved away from adding the regular bonuses and just relied on terminal bonus.
That's my recollection of the traditional (not unitised) with profit model.