The right-hand long arm for your 18' Lippert Solera awning can be purchased separately. Based on your description and measurements, the New Lippert Style Edge or 2000 Series Top Inner Arm Replacement Part measuring 46 1/8" is the correct fit. This part includes the arm itself, and you will need snap rings for reattachment since the existing ones are not reusable; pins are still good as you mentioned. To proceed, please confirm whether your awning is manual or power-operated and the arm color (black or white), so we can ensure the correct replacement and hardware. We can assist you with pricing and placing an order once these details are confirmed. Genuine replacement parts ensure proper fit and durability for your 2021 Forest River Sabre's awning repair.