Most would consider that a custom rifle. However, lapping the lugs is not a great idea for older, surface-hardened actions because the 'smith could easily cut through the very thin hardened shell and ruin the action. This isn't the 1950s - when spending the money for a custom rifle today, use a modern action rather than an old beat up military action. The new action will not require drilling and tapping for a scope, it won't need to be polished and blued, it won't need a special safety, special trigger.....the list goes on. You will be happier with the new action, and the cost will be similar if not less than the old military action.
Regardless of what you call it, if it is done right your idea would result in a very nice rifle.
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