Less is more. Stay pure. Stay poor.
If you don't have a holdout set, you would not turn around and use LASSO model terms in an OLS model, you would use output from the LASSO model. If you had a holdout set, you then can use the variables selected from the LASSO in the OLS and the OLS estimates. You don't get your cake and eat it, when you don't have a holdout set.