I'm not sure what you're seeing but my phone does not have a push option in the native email app.
Well, on the HTC mail app (not gmail), when I press the menu button, I see a menu with 6 options: "Refresh", "Sort", "Compose", "Folders", "Account list", and "More".
If I press "More", I get a popup list with four entries: "New meeting invitation", "New account" "Out of office", and "Settings'.
If I press "Settings", I get a screen with my account name at the top and five options: "Account settings", "General settings", "Send & Receive", "Notification settings", and "Delete account".
If I press "Send & Receive", I see a screen with a whole bunch of settings, the first three of which are "Mail size limit", "Message format", and "Update schedule".
If I press "Update schedule", I see a screen with settings to describe when "Peak time" is, and then two settings to set the update schedule for "Peak times" and "Off-peak times".
If I press either of these, I get a popup list with "Push Mail", "Every 5 minutes", "Every 10 minutes", "Every 15 minutes", etc