I don't think so, so long as the benefit remains forfeitable (as it has to be for a 457(f) plan). Under section 402(B)(1),
QUOTE
Contributions to an employees' trust made by an employer during a taxable year of the employer which ends with or within a taxable year of the trust for which the trust is not exempt from tax under section 501(a) shall be included in the gross income of the employee in accordance with section 83 (relating to property transferred in connection with performance of services), except that the value of the employee's interest in the trust shall be substituted for the fair market value of the property for purposes of applying such section.
Under section 83,
QUOTE
If, in connection with the performance of services, property is transferred to any person other than the person for whom such services are performed, the excess of--[list=1]
[*]the fair market value of such property (determined without regard to any restriction other than a restriction which by its terms will never lapse) at the first time the rights of the person having the beneficial interest in such property are transferable or are not subject to a substantial risk of forfeiture, whichever occurs earlier, over
[*] the amount (if any) paid for such property[/list=1]shall be included in the gross income of the person who performed such services in the first taxable year in which the rights of the person having the beneficial interest in such property are transferable or are not subject to a substantial risk of forfeiture, whichever is applicable. The preceding sentence shall not apply if such person sells or otherwise disposes of such property in an arm's length transaction before his rights in such property become transferable or not subject to a substantial risk of forfeiture.
Thus, the participant should not be taxed on these accruals until the rights in the trust become transferable or not subject to a substantial risk of forfeiture--which is exactly when rights in a 457(f) plan would become taxable.